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ATS/T\ATS12
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
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| Tape/disk: | Home » CEEFAX disks » telesoftware2.adl |
| Filename: | ATS/T\ATS12 |
| Read OK: | ✔ |
| File size: | 34E4 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Interactive programming J.J.Brayshaw 1987
ATS12: Simultaneous Page Grabbers
=================================
Earlier modules have demonstrated the ease with which a single page can be
received and processed. However, some applications require data to be
extracted from several CEEFAX pages at once. The adapter is capable of
receiving up to 20 CEEFAX pages at the same time ...
__________________________________________________________________________
The Acorn adapter with ATS is capable of looking for up to 20 teletext
pages at the same time (thanks to its use of very versatile teletext
reception micro-chips).
The by now familiar command "*PAGE xxx" gets the adapter to search for a
specific CEEFAX page, but it may not be so obvious that only one of the
possible 20 "page grabbers" is being used. Another "*PAGE" command
requesting a different page simply re-sets the same one page grabber to
look for a different page - still only the one page grabber in use.
The remaining 19 page grabbers cannot be engaged by using the simple *PAGE
instruction, but require specific O.S. calls to get them going.
The page grabbers are numbered 0 to 19. To set any page grabber to receive
a specific page, ATS must be told:
(a) which page grabber to use (0 to 19)
(b) what magazine, page and sub-page to search for
(c) where in computer memory to store the page
When 20 pages are being grabbed, a sizable chunk of memory is used leaving
very little for processing the data. However, the amount of data
transferred from each page grabber can be restricted. In fact there are
several OSWORD calls relating to the page grabbing operation, and each is
briefly described below. See the associated program (B/ATS12) to see how
most of them can be implemented.
Set number of rows to be captured:
==================================
To limit the reception of a page to a certain number of teletext rows.
This makes it easy to calculate the maximum amount of memory that may be
needed to store the page, and eliminates the possibility of overflowing
the allocated space by receiving unwanted rows. Depending on what you want
to do with the page received, it is best to limit the page size to 24 rows
(for the readable part of the page only) or 27 rows (if a CRC or the page
link information is required). To adjust this figure in the program, alter
the variable "page_length%" in the first few lines.
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Interactive programming J.J.Brayshaw 1987
Read number of rows to be captured:
===================================
Having already set the number of rows (or packets) the page grabbers are
to receive, your program shouldn't need to make this OSWORD call. It will
tell you the maximum row number plus 1 that the page grabber will receive
when a page is grabbed. (i.e. if the call returns "20", the page grabber
is set to receive any packets numbered 0 to 19 inclusive).
Set a page grabber record:
==========================
This call must be made once for each page grabber you want to use. It
begins teletext reception immediately, and does not wait for the requested
page to be received. To adjust the program B/ATS12 to use fewer page
grabbers, alter the variable "qty%", then adjust the DATA statement to
give your chosen page numbers. Remember that the same page must not be
requested from two different page grabbers, unless different sub-page
numbers are specified.
Read a page grabber record:
===========================
Normally, you are unlikely to want to read the information about a
particular record - having set the record earlier your program should
already know this. However, more complex programs may, for example, set a
page grabber from received information such as the page link settings, and
a scan of the current grabber details could determine whether another page
grabber has already been set to receive the page. It is important not to
set two page grabbers to receive the same page as the higher numbered page
grabber will never receive it! (It is possible to set two different page
grabbers to receive different sub-pages from the same page, however.)
Read a record flag:
===================
The "record flag" gives important information about the current status of
the particular page grabber - whether the page is being received at the
moment the call is made, whether it has been previously received, or
whether it is "on hold".
Set a record flag:
==================
This allows us to put a specific page grabber on hold (i.e. to prevent the
page being overwritten by any subsequently received versions) or to
release it (so subsequent page reception overwrites the previous version).
Clear all page grabber records:
===============================
Used to reset all the page grabbers so they are no longer searching for
CEEFAX pages. To clear a single page grabber is not possible, but the same
Page 2
Interactive programming J.J.Brayshaw 1987
effect can be achieved by putting the appropriate grabber on "hold". Page
grabbers can be re-set to receive a different page without having to be
disabled first.
Once engaged, a page grabber continues to receive the requested page until
cancelled. As this is an "interrupt" process, it will continue to receive
and transfer pages even after the program ends! It is, therefore, very
important to turn off the page grabbers before leaving the program.
*TTXOFF will achieve this, but is a drastic and not very elegant method
(rather like BREAK is to a BASIC program). An ATS OSWORD call is provided
to stop the page grabbers receiving pages.
Any attempt to alter or reset a page grabber during the actual reception
of a page should be avoided. The program B/ATS12 carries out several
processes before disabling the page grabbers:
(1) Each page grabber is interrogated to ensure a page has actually been
received. The OSWORD call to set a page grabber returns control to your
program immediately, and, unlike the *TRANSFER command, does not wait
until a page has been received. It is therefore important to check each
page grabber has got a page before trying to use the information from the
page!
(2) Each page grabber is interrogated to ensure it is not currently in the
process of being updated (i.e. it is not part-way through receiving a
page).
(3) If the page grabber has received a page, and it is not currently being
updated, it is put into "Hold Page" mode. In this state, the page grabber
is still set to find the requested page, but does not transfer the page
when found. This ensures that any processing that we carry out on the page
is not subsequently overwritten by another incoming page. The page grabber
could, of course, be re-enabled (taken off "hold") at any time if
required.
(4) When all the page grabbers have been set on "hold", processing of the
data can be carried out without any fear of the page details being altered
during processing by an incoming page.
(5) The details for the VidiEd magazine file are saved, then the page
grabbers are all disabled before the program terminated.
The first point makes using page grabbers (as opposed to receiving a page
with the *PAGE and *TRANSFER commands) a very efficient method of
receiving teletext. It offers numerous advantages:
- the page is kept up-to-date at all times without further intervention.
(Try adjusting the program so you enter VidiEd immediately after
Page 3
Interactive programming J.J.Brayshaw 1987
setting the page grabbers. This will destroy the resident program, but
the page grabbers will still be active, giving you a "live" Vidied
magazine!)
- other processing can be carried out between requesting a page and it
being received. Using *TRANSFER or *DATA halts the program until the
page has been received.
- it becomes possible to determine whether a page is actually being
broadcast or not. The time between requesting and receiving a page can
be measured. If this time exceeds a pre-determined limit, it can be
assumed the page does not exist and the program can then take suitable
action.
When using page grabbers to save pages to a specific area of memory, it is
vital that your BASIC program knows it must not overwrite this area with
other data. The easiest way to achieve this is to use a DIM statement to
reserve sufficient space (for example:
DIM space% 20*&3C0
to reserve an area large enough to store 20 pages each restricted to 24
lines). Because the VidiEd program uses a specific area of memory, B/ATS12
does not use the above method. Instead it brings HIMEM down to below the
lowest area in memory the pages will be stored (in this case &2C00). This
prevents BASIC using any of the space above this for variables etc. The
former method is probably more efficient in terms of memory requirements,
but would not be very practical in this particular situation. Whatever the
application, steps must be taken to ensure the page-store memory is not
used for any other purpose.
The latest teletext development, the FLOF (or FASTEXT) system, was
described in detail in an earlier module. It uses some of the page links,
which requires at least six page grabbers to be active. This system is
implemented in the normal ATS teletext reception mode. When a page is
requested, it activates page grabber zero. When it is received, the links
are decoded and page grabbers 1 to 4 are set to receive the pages pointed
to by the first four links. Link 5 (the sixth link) is the "Index" page
which is allocated to the next page grabber. As many of the remaining page
grabbers as possible (depending on the available memory) are set to
receive any user-requested pages, as indicated by the "keep page"
facility. In this way, all these pages should be ready for immediate
display if requested. Each page stored by the ATS must include the full
page data (i.e.as many packets as are transmitted) and therefore at least
2k of memory must be available for each page stored in this way.
*NOTE: Some makes of teletext adapter use newer, but less versatile,
teletext reception micro-chips. Because of the more limited control these
allow, only one page grabber can be used. The routines described here are
not implemented on such adapters, although for the sake of compatibility
Page 4
Interactive programming J.J.Brayshaw 1987
their version of ATS will not generate an error. This explains why, with
such adapters, the FLOF system does not instantly display a linked page,
but merely tells the only page grabber available to get the linked page
upon its next broadcast.
Using the page grabbers included with ATS and the Acorn adapter removes
the limitations imposed by the single-page transfer commands *PAGE,
*TRANSFER and *DATA. Not all 20 grabbers have to be set - you can use any
quantity from 1 to 20 - which means almost any teletext application can be
improved and speeded up by using this method of page reception.
__________________________________________________________________________
B/ATS12 will capture each of the news pages broadcast by CEEFAX, as well
as the main index page, the financial index page and the news index page.
It sets all 20 page grabbers then waits until each grabber indicates it
has captured a page. (During this time, the program could be made to do
other things.)
Once captured, each page grabbed can be displayed. The page captured by
the first page grabber is shewn. (record number zero). By pressing the
left or right arrow key, all the pages in the sequence can be seen. To
prove the grabbers are still active, try finding a page with more than one
sub-page. The page grabber is set to update the page in memory, not on the
screen, so to see any change in the page you will need to move to another
page and back again!
You can cycle through the pages at will, using the left arrow to move down
the sequence, and the right arrow to move up.
Upon pressing the SPACE BAR, the program carries out the sequence of
operations described above to disable the page grabbers. Once this has
been done, each page is given a suitable header and all the records are
saved as a single VidiEd magazine. If you now enter VidiEd and re-load the
magazine (called "CEEFAX" and saved in the "D" directory) you can see, by
typing MAGAZINE on the command line, the time each page was captured.
*DATA or *TRANSFER would have meant a gap of around 20 seconds between
reception of each page - a total of around 7 minutes. By using the page
grabbers we can capture all 20 pages within a single CEEFAX cycle (i.e.
less than 20 seconds and sometimes in as little as two seconds!) saving
over six minutes!
ADFS users will need to adjust the file name under which the VidiEd
magazine is saved, to exclude the reference to the "D" directory. The
appropriate line in the program is preceded by an identifying REM
statement.
If you do not have a copy of the VidiEd program, don't worry - it will be
Page 5
Interactive programming J.J.Brayshaw 1987
re-broadcast next week. In the meantime, have fun grabbing CEEFAX by the
score!
Page 6
00000000 0d 0d 0d 0d 49 6e 74 65 72 61 63 74 69 76 65 20 |....Interactive | 00000010 70 72 6f 67 72 61 6d 6d 69 6e 67 20 20 20 20 20 |programming | 00000020 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000030 20 20 20 20 20 20 20 20 20 20 20 20 20 4a 2e 4a | J.J| 00000040 2e 42 72 61 79 73 68 61 77 20 31 39 38 37 0d 0d |.Brayshaw 1987..| 00000050 0d 0d 0d 41 54 53 31 32 3a 20 53 69 6d 75 6c 74 |...ATS12: Simult| 00000060 61 6e 65 6f 75 73 20 50 61 67 65 20 47 72 61 62 |aneous Page Grab| 00000070 62 65 72 73 0d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |bers.===========| 00000080 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000090 3d 3d 3d 3d 3d 3d 0d 0d 45 61 72 6c 69 65 72 20 |======..Earlier | 000000a0 6d 6f 64 75 6c 65 73 20 68 61 76 65 20 64 65 6d |modules have dem| 000000b0 6f 6e 73 74 72 61 74 65 64 20 74 68 65 20 65 61 |onstrated the ea| 000000c0 73 65 20 77 69 74 68 20 77 68 69 63 68 20 61 20 |se with which a | 000000d0 73 69 6e 67 6c 65 20 70 61 67 65 20 63 61 6e 20 |single page can | 000000e0 62 65 0d 72 65 63 65 69 76 65 64 20 61 6e 64 20 |be.received and | 000000f0 70 72 6f 63 65 73 73 65 64 2e 20 48 6f 77 65 76 |processed. Howev| 00000100 65 72 2c 20 73 6f 6d 65 20 61 70 70 6c 69 63 61 |er, some applica| 00000110 74 69 6f 6e 73 20 72 65 71 75 69 72 65 20 64 61 |tions require da| 00000120 74 61 20 74 6f 20 62 65 0d 65 78 74 72 61 63 74 |ta to be.extract| 00000130 65 64 20 66 72 6f 6d 20 73 65 76 65 72 61 6c 20 |ed from several | 00000140 43 45 45 46 41 58 20 70 61 67 65 73 20 61 74 20 |CEEFAX pages at | 00000150 6f 6e 63 65 2e 20 54 68 65 20 61 64 61 70 74 65 |once. The adapte| 00000160 72 20 69 73 20 63 61 70 61 62 6c 65 20 6f 66 0d |r is capable of.| 00000170 72 65 63 65 69 76 69 6e 67 20 75 70 20 74 6f 20 |receiving up to | 00000180 32 30 20 43 45 45 46 41 58 20 70 61 67 65 73 20 |20 CEEFAX pages | 00000190 61 74 20 74 68 65 20 73 61 6d 65 20 74 69 6d 65 |at the same time| 000001a0 20 2e 2e 2e 0d 0d 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f | .....__________| 000001b0 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f |________________| * 000001f0 0d 0d 0d 54 68 65 20 41 63 6f 72 6e 20 61 64 61 |...The Acorn ada| 00000200 70 74 65 72 20 77 69 74 68 20 41 54 53 20 69 73 |pter with ATS is| 00000210 20 63 61 70 61 62 6c 65 20 6f 66 20 6c 6f 6f 6b | capable of look| 00000220 69 6e 67 20 66 6f 72 20 75 70 20 74 6f 20 32 30 |ing for up to 20| 00000230 20 74 65 6c 65 74 65 78 74 0d 70 61 67 65 73 20 | teletext.pages | 00000240 61 74 20 74 68 65 20 73 61 6d 65 20 74 69 6d 65 |at the same time| 00000250 20 28 74 68 61 6e 6b 73 20 74 6f 20 69 74 73 20 | (thanks to its | 00000260 75 73 65 20 6f 66 20 76 65 72 79 20 76 65 72 73 |use of very vers| 00000270 61 74 69 6c 65 20 74 65 6c 65 74 65 78 74 0d 72 |atile teletext.r| 00000280 65 63 65 70 74 69 6f 6e 20 6d 69 63 72 6f 2d 63 |eception micro-c| 00000290 68 69 70 73 29 2e 0d 0d 54 68 65 20 62 79 20 6e |hips)...The by n| 000002a0 6f 77 20 66 61 6d 69 6c 69 61 72 20 63 6f 6d 6d |ow familiar comm| 000002b0 61 6e 64 20 22 2a 50 41 47 45 20 78 78 78 22 20 |and "*PAGE xxx" | 000002c0 67 65 74 73 20 74 68 65 20 61 64 61 70 74 65 72 |gets the adapter| 000002d0 20 74 6f 20 73 65 61 72 63 68 20 66 6f 72 20 61 | to search for a| 000002e0 0d 73 70 65 63 69 66 69 63 20 43 45 45 46 41 58 |.specific CEEFAX| 000002f0 20 70 61 67 65 2c 20 62 75 74 20 69 74 20 6d 61 | page, but it ma| 00000300 79 20 6e 6f 74 20 62 65 20 73 6f 20 6f 62 76 69 |y not be so obvi| 00000310 6f 75 73 20 74 68 61 74 20 6f 6e 6c 79 20 6f 6e |ous that only on| 00000320 65 20 6f 66 20 74 68 65 0d 70 6f 73 73 69 62 6c |e of the.possibl| 00000330 65 20 32 30 20 22 70 61 67 65 20 67 72 61 62 62 |e 20 "page grabb| 00000340 65 72 73 22 20 69 73 20 62 65 69 6e 67 20 75 73 |ers" is being us| 00000350 65 64 2e 20 41 6e 6f 74 68 65 72 20 22 2a 50 41 |ed. Another "*PA| 00000360 47 45 22 20 63 6f 6d 6d 61 6e 64 0d 72 65 71 75 |GE" command.requ| 00000370 65 73 74 69 6e 67 20 61 20 64 69 66 66 65 72 65 |esting a differe| 00000380 6e 74 20 70 61 67 65 20 73 69 6d 70 6c 79 20 72 |nt page simply r| 00000390 65 2d 73 65 74 73 20 74 68 65 20 73 61 6d 65 20 |e-sets the same | 000003a0 6f 6e 65 20 70 61 67 65 20 67 72 61 62 62 65 72 |one page grabber| 000003b0 20 74 6f 0d 6c 6f 6f 6b 20 66 6f 72 20 61 20 64 | to.look for a d| 000003c0 69 66 66 65 72 65 6e 74 20 70 61 67 65 20 2d 20 |ifferent page - | 000003d0 73 74 69 6c 6c 20 6f 6e 6c 79 20 74 68 65 20 6f |still only the o| 000003e0 6e 65 20 70 61 67 65 20 67 72 61 62 62 65 72 20 |ne page grabber | 000003f0 69 6e 20 75 73 65 2e 0d 0d 54 68 65 20 72 65 6d |in use...The rem| 00000400 61 69 6e 69 6e 67 20 31 39 20 70 61 67 65 20 67 |aining 19 page g| 00000410 72 61 62 62 65 72 73 20 63 61 6e 6e 6f 74 20 62 |rabbers cannot b| 00000420 65 20 65 6e 67 61 67 65 64 20 62 79 20 75 73 69 |e engaged by usi| 00000430 6e 67 20 74 68 65 20 73 69 6d 70 6c 65 20 2a 50 |ng the simple *P| 00000440 41 47 45 0d 69 6e 73 74 72 75 63 74 69 6f 6e 2c |AGE.instruction,| 00000450 20 62 75 74 20 72 65 71 75 69 72 65 20 73 70 65 | but require spe| 00000460 63 69 66 69 63 20 4f 2e 53 2e 20 63 61 6c 6c 73 |cific O.S. calls| 00000470 20 74 6f 20 67 65 74 20 74 68 65 6d 20 67 6f 69 | to get them goi| 00000480 6e 67 2e 0d 0d 54 68 65 20 70 61 67 65 20 67 72 |ng...The page gr| 00000490 61 62 62 65 72 73 20 61 72 65 20 6e 75 6d 62 65 |abbers are numbe| 000004a0 72 65 64 20 30 20 74 6f 20 31 39 2e 20 54 6f 20 |red 0 to 19. To | 000004b0 73 65 74 20 61 6e 79 20 70 61 67 65 20 67 72 61 |set any page gra| 000004c0 62 62 65 72 20 74 6f 20 72 65 63 65 69 76 65 0d |bber to receive.| 000004d0 61 20 73 70 65 63 69 66 69 63 20 70 61 67 65 2c |a specific page,| 000004e0 20 41 54 53 20 6d 75 73 74 20 62 65 20 74 6f 6c | ATS must be tol| 000004f0 64 3a 0d 0d 28 61 29 20 77 68 69 63 68 20 70 61 |d:..(a) which pa| 00000500 67 65 20 67 72 61 62 62 65 72 20 74 6f 20 75 73 |ge grabber to us| 00000510 65 20 28 30 20 74 6f 20 31 39 29 0d 28 62 29 20 |e (0 to 19).(b) | 00000520 77 68 61 74 20 6d 61 67 61 7a 69 6e 65 2c 20 70 |what magazine, p| 00000530 61 67 65 20 61 6e 64 20 73 75 62 2d 70 61 67 65 |age and sub-page| 00000540 20 74 6f 20 73 65 61 72 63 68 20 66 6f 72 0d 28 | to search for.(| 00000550 63 29 20 77 68 65 72 65 20 69 6e 20 63 6f 6d 70 |c) where in comp| 00000560 75 74 65 72 20 6d 65 6d 6f 72 79 20 74 6f 20 73 |uter memory to s| 00000570 74 6f 72 65 20 74 68 65 20 70 61 67 65 0d 0d 57 |tore the page..W| 00000580 68 65 6e 20 32 30 20 70 61 67 65 73 20 61 72 65 |hen 20 pages are| 00000590 20 62 65 69 6e 67 20 67 72 61 62 62 65 64 2c 20 | being grabbed, | 000005a0 61 20 73 69 7a 61 62 6c 65 20 63 68 75 6e 6b 20 |a sizable chunk | 000005b0 6f 66 20 6d 65 6d 6f 72 79 20 69 73 20 75 73 65 |of memory is use| 000005c0 64 20 6c 65 61 76 69 6e 67 0d 76 65 72 79 20 6c |d leaving.very l| 000005d0 69 74 74 6c 65 20 66 6f 72 20 70 72 6f 63 65 73 |ittle for proces| 000005e0 73 69 6e 67 20 74 68 65 20 64 61 74 61 2e 20 48 |sing the data. H| 000005f0 6f 77 65 76 65 72 2c 20 74 68 65 20 61 6d 6f 75 |owever, the amou| 00000600 6e 74 20 6f 66 20 64 61 74 61 0d 74 72 61 6e 73 |nt of data.trans| 00000610 66 65 72 72 65 64 20 66 72 6f 6d 20 65 61 63 68 |ferred from each| 00000620 20 70 61 67 65 20 67 72 61 62 62 65 72 20 63 61 | page grabber ca| 00000630 6e 20 62 65 20 72 65 73 74 72 69 63 74 65 64 2e |n be restricted.| 00000640 20 49 6e 20 66 61 63 74 20 74 68 65 72 65 20 61 | In fact there a| 00000650 72 65 0d 73 65 76 65 72 61 6c 20 4f 53 57 4f 52 |re.several OSWOR| 00000660 44 20 63 61 6c 6c 73 20 72 65 6c 61 74 69 6e 67 |D calls relating| 00000670 20 74 6f 20 74 68 65 20 70 61 67 65 20 67 72 61 | to the page gra| 00000680 62 62 69 6e 67 20 6f 70 65 72 61 74 69 6f 6e 2c |bbing operation,| 00000690 20 61 6e 64 20 65 61 63 68 20 69 73 0d 62 72 69 | and each is.bri| 000006a0 65 66 6c 79 20 64 65 73 63 72 69 62 65 64 20 62 |efly described b| 000006b0 65 6c 6f 77 2e 20 53 65 65 20 74 68 65 20 61 73 |elow. See the as| 000006c0 73 6f 63 69 61 74 65 64 20 70 72 6f 67 72 61 6d |sociated program| 000006d0 20 28 42 2f 41 54 53 31 32 29 20 74 6f 20 73 65 | (B/ATS12) to se| 000006e0 65 20 68 6f 77 0d 6d 6f 73 74 20 6f 66 20 74 68 |e how.most of th| 000006f0 65 6d 20 63 61 6e 20 62 65 20 69 6d 70 6c 65 6d |em can be implem| 00000700 65 6e 74 65 64 2e 0d 0d 53 65 74 20 6e 75 6d 62 |ented...Set numb| 00000710 65 72 20 6f 66 20 72 6f 77 73 20 74 6f 20 62 65 |er of rows to be| 00000720 20 63 61 70 74 75 72 65 64 3a 0d 3d 3d 3d 3d 3d | captured:.=====| 00000730 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000740 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0d 54 6f |=============.To| 00000750 20 6c 69 6d 69 74 20 74 68 65 20 72 65 63 65 70 | limit the recep| 00000760 74 69 6f 6e 20 6f 66 20 61 20 70 61 67 65 20 74 |tion of a page t| 00000770 6f 20 61 20 63 65 72 74 61 69 6e 20 6e 75 6d 62 |o a certain numb| 00000780 65 72 20 6f 66 20 74 65 6c 65 74 65 78 74 20 72 |er of teletext r| 00000790 6f 77 73 2e 0d 54 68 69 73 20 6d 61 6b 65 73 20 |ows..This makes | 000007a0 69 74 20 65 61 73 79 20 74 6f 20 63 61 6c 63 75 |it easy to calcu| 000007b0 6c 61 74 65 20 74 68 65 20 6d 61 78 69 6d 75 6d |late the maximum| 000007c0 20 61 6d 6f 75 6e 74 20 6f 66 20 6d 65 6d 6f 72 | amount of memor| 000007d0 79 20 74 68 61 74 20 6d 61 79 20 62 65 0d 6e 65 |y that may be.ne| 000007e0 65 64 65 64 20 74 6f 20 73 74 6f 72 65 20 74 68 |eded to store th| 000007f0 65 20 70 61 67 65 2c 20 61 6e 64 20 65 6c 69 6d |e page, and elim| 00000800 69 6e 61 74 65 73 20 74 68 65 20 70 6f 73 73 69 |inates the possi| 00000810 62 69 6c 69 74 79 20 6f 66 20 6f 76 65 72 66 6c |bility of overfl| 00000820 6f 77 69 6e 67 0d 74 68 65 20 61 6c 6c 6f 63 61 |owing.the alloca| 00000830 74 65 64 20 73 70 61 63 65 20 62 79 20 72 65 63 |ted space by rec| 00000840 65 69 76 69 6e 67 20 75 6e 77 61 6e 74 65 64 20 |eiving unwanted | 00000850 72 6f 77 73 2e 20 44 65 70 65 6e 64 69 6e 67 20 |rows. Depending | 00000860 6f 6e 20 77 68 61 74 20 79 6f 75 20 77 61 6e 74 |on what you want| 00000870 0d 74 6f 20 64 6f 20 77 69 74 68 20 74 68 65 20 |.to do with the | 00000880 70 61 67 65 20 72 65 63 65 69 76 65 64 2c 20 69 |page received, i| 00000890 74 20 69 73 20 62 65 73 74 20 74 6f 20 6c 69 6d |t is best to lim| 000008a0 69 74 20 74 68 65 20 70 61 67 65 20 73 69 7a 65 |it the page size| 000008b0 20 74 6f 20 32 34 20 72 6f 77 73 0d 28 66 6f 72 | to 24 rows.(for| 000008c0 20 74 68 65 20 72 65 61 64 61 62 6c 65 20 70 61 | the readable pa| 000008d0 72 74 20 6f 66 20 74 68 65 20 70 61 67 65 20 6f |rt of the page o| 000008e0 6e 6c 79 29 20 6f 72 20 32 37 20 72 6f 77 73 20 |nly) or 27 rows | 000008f0 28 69 66 20 61 20 43 52 43 20 6f 72 20 74 68 65 |(if a CRC or the| 00000900 20 70 61 67 65 0d 6c 69 6e 6b 20 69 6e 66 6f 72 | page.link infor| 00000910 6d 61 74 69 6f 6e 20 69 73 20 72 65 71 75 69 72 |mation is requir| 00000920 65 64 29 2e 20 54 6f 20 61 64 6a 75 73 74 20 74 |ed). To adjust t| 00000930 68 69 73 20 66 69 67 75 72 65 20 69 6e 20 74 68 |his figure in th| 00000940 65 20 70 72 6f 67 72 61 6d 2c 20 61 6c 74 65 72 |e program, alter| 00000950 0d 74 68 65 20 76 61 72 69 61 62 6c 65 20 22 70 |.the variable "p| 00000960 61 67 65 5f 6c 65 6e 67 74 68 25 22 20 69 6e 20 |age_length%" in | 00000970 74 68 65 20 66 69 72 73 74 20 66 65 77 20 6c 69 |the first few li| 00000980 6e 65 73 2e 0d 0d 0d 0d 0d 20 20 20 20 20 20 20 |nes...... | 00000990 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000009a0 20 20 20 20 20 20 20 20 20 20 20 50 61 67 65 20 | Page | 000009b0 31 0d 0d 0d 0d 0d 0d 0d 0d 0d 49 6e 74 65 72 61 |1.........Intera| 000009c0 63 74 69 76 65 20 70 72 6f 67 72 61 6d 6d 69 6e |ctive programmin| 000009d0 67 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |g | 000009e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000009f0 20 20 20 4a 2e 4a 2e 42 72 61 79 73 68 61 77 20 | J.J.Brayshaw | 00000a00 31 39 38 37 0d 0d 0d 0d 0d 0d 52 65 61 64 20 6e |1987......Read n| 00000a10 75 6d 62 65 72 20 6f 66 20 72 6f 77 73 20 74 6f |umber of rows to| 00000a20 20 62 65 20 63 61 70 74 75 72 65 64 3a 0d 3d 3d | be captured:.==| 00000a30 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| * 00000a50 3d 0d 48 61 76 69 6e 67 20 61 6c 72 65 61 64 79 |=.Having already| 00000a60 20 73 65 74 20 74 68 65 20 6e 75 6d 62 65 72 20 | set the number | 00000a70 6f 66 20 72 6f 77 73 20 28 6f 72 20 70 61 63 6b |of rows (or pack| 00000a80 65 74 73 29 20 74 68 65 20 70 61 67 65 20 67 72 |ets) the page gr| 00000a90 61 62 62 65 72 73 20 61 72 65 0d 74 6f 20 72 65 |abbers are.to re| 00000aa0 63 65 69 76 65 2c 20 79 6f 75 72 20 70 72 6f 67 |ceive, your prog| 00000ab0 72 61 6d 20 73 68 6f 75 6c 64 6e 27 74 20 6e 65 |ram shouldn't ne| 00000ac0 65 64 20 74 6f 20 6d 61 6b 65 20 74 68 69 73 20 |ed to make this | 00000ad0 4f 53 57 4f 52 44 20 63 61 6c 6c 2e 20 49 74 20 |OSWORD call. It | 00000ae0 77 69 6c 6c 0d 74 65 6c 6c 20 79 6f 75 20 74 68 |will.tell you th| 00000af0 65 20 6d 61 78 69 6d 75 6d 20 72 6f 77 20 6e 75 |e maximum row nu| 00000b00 6d 62 65 72 20 70 6c 75 73 20 31 20 74 68 61 74 |mber plus 1 that| 00000b10 20 74 68 65 20 70 61 67 65 20 67 72 61 62 62 65 | the page grabbe| 00000b20 72 20 77 69 6c 6c 20 72 65 63 65 69 76 65 0d 77 |r will receive.w| 00000b30 68 65 6e 20 61 20 70 61 67 65 20 69 73 20 67 72 |hen a page is gr| 00000b40 61 62 62 65 64 2e 20 28 69 2e 65 2e 20 69 66 20 |abbed. (i.e. if | 00000b50 74 68 65 20 63 61 6c 6c 20 72 65 74 75 72 6e 73 |the call returns| 00000b60 20 22 32 30 22 2c 20 74 68 65 20 70 61 67 65 20 | "20", the page | 00000b70 67 72 61 62 62 65 72 0d 69 73 20 73 65 74 20 74 |grabber.is set t| 00000b80 6f 20 72 65 63 65 69 76 65 20 61 6e 79 20 70 61 |o receive any pa| 00000b90 63 6b 65 74 73 20 6e 75 6d 62 65 72 65 64 20 30 |ckets numbered 0| 00000ba0 20 74 6f 20 31 39 20 69 6e 63 6c 75 73 69 76 65 | to 19 inclusive| 00000bb0 29 2e 0d 0d 53 65 74 20 61 20 70 61 67 65 20 67 |)...Set a page g| 00000bc0 72 61 62 62 65 72 20 72 65 63 6f 72 64 3a 0d 3d |rabber record:.=| 00000bd0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000be0 3d 3d 3d 3d 3d 3d 3d 3d 3d 0d 54 68 69 73 20 63 |=========.This c| 00000bf0 61 6c 6c 20 6d 75 73 74 20 62 65 20 6d 61 64 65 |all must be made| 00000c00 20 6f 6e 63 65 20 66 6f 72 20 65 61 63 68 20 70 | once for each p| 00000c10 61 67 65 20 67 72 61 62 62 65 72 20 79 6f 75 20 |age grabber you | 00000c20 77 61 6e 74 20 74 6f 20 75 73 65 2e 20 49 74 0d |want to use. It.| 00000c30 62 65 67 69 6e 73 20 74 65 6c 65 74 65 78 74 20 |begins teletext | 00000c40 72 65 63 65 70 74 69 6f 6e 20 69 6d 6d 65 64 69 |reception immedi| 00000c50 61 74 65 6c 79 2c 20 61 6e 64 20 64 6f 65 73 20 |ately, and does | 00000c60 6e 6f 74 20 77 61 69 74 20 66 6f 72 20 74 68 65 |not wait for the| 00000c70 20 72 65 71 75 65 73 74 65 64 0d 70 61 67 65 20 | requested.page | 00000c80 74 6f 20 62 65 20 72 65 63 65 69 76 65 64 2e 20 |to be received. | 00000c90 54 6f 20 61 64 6a 75 73 74 20 74 68 65 20 70 72 |To adjust the pr| 00000ca0 6f 67 72 61 6d 20 42 2f 41 54 53 31 32 20 74 6f |ogram B/ATS12 to| 00000cb0 20 75 73 65 20 66 65 77 65 72 20 70 61 67 65 0d | use fewer page.| 00000cc0 67 72 61 62 62 65 72 73 2c 20 61 6c 74 65 72 20 |grabbers, alter | 00000cd0 74 68 65 20 76 61 72 69 61 62 6c 65 20 22 71 74 |the variable "qt| 00000ce0 79 25 22 2c 20 74 68 65 6e 20 61 64 6a 75 73 74 |y%", then adjust| 00000cf0 20 74 68 65 20 44 41 54 41 20 73 74 61 74 65 6d | the DATA statem| 00000d00 65 6e 74 20 74 6f 0d 67 69 76 65 20 79 6f 75 72 |ent to.give your| 00000d10 20 63 68 6f 73 65 6e 20 70 61 67 65 20 6e 75 6d | chosen page num| 00000d20 62 65 72 73 2e 20 52 65 6d 65 6d 62 65 72 20 74 |bers. Remember t| 00000d30 68 61 74 20 74 68 65 20 73 61 6d 65 20 70 61 67 |hat the same pag| 00000d40 65 20 6d 75 73 74 20 6e 6f 74 20 62 65 0d 72 65 |e must not be.re| 00000d50 71 75 65 73 74 65 64 20 66 72 6f 6d 20 74 77 6f |quested from two| 00000d60 20 64 69 66 66 65 72 65 6e 74 20 70 61 67 65 20 | different page | 00000d70 67 72 61 62 62 65 72 73 2c 20 75 6e 6c 65 73 73 |grabbers, unless| 00000d80 20 64 69 66 66 65 72 65 6e 74 20 73 75 62 2d 70 | different sub-p| 00000d90 61 67 65 0d 6e 75 6d 62 65 72 73 20 61 72 65 20 |age.numbers are | 00000da0 73 70 65 63 69 66 69 65 64 2e 0d 0d 52 65 61 64 |specified...Read| 00000db0 20 61 20 70 61 67 65 20 67 72 61 62 62 65 72 20 | a page grabber | 00000dc0 72 65 63 6f 72 64 3a 0d 3d 3d 3d 3d 3d 3d 3d 3d |record:.========| 00000dd0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000de0 3d 3d 3d 0d 4e 6f 72 6d 61 6c 6c 79 2c 20 79 6f |===.Normally, yo| 00000df0 75 20 61 72 65 20 75 6e 6c 69 6b 65 6c 79 20 74 |u are unlikely t| 00000e00 6f 20 77 61 6e 74 20 74 6f 20 72 65 61 64 20 74 |o want to read t| 00000e10 68 65 20 69 6e 66 6f 72 6d 61 74 69 6f 6e 20 61 |he information a| 00000e20 62 6f 75 74 20 61 0d 70 61 72 74 69 63 75 6c 61 |bout a.particula| 00000e30 72 20 72 65 63 6f 72 64 20 2d 20 68 61 76 69 6e |r record - havin| 00000e40 67 20 73 65 74 20 74 68 65 20 72 65 63 6f 72 64 |g set the record| 00000e50 20 65 61 72 6c 69 65 72 20 79 6f 75 72 20 70 72 | earlier your pr| 00000e60 6f 67 72 61 6d 20 73 68 6f 75 6c 64 0d 61 6c 72 |ogram should.alr| 00000e70 65 61 64 79 20 6b 6e 6f 77 20 74 68 69 73 2e 20 |eady know this. | 00000e80 48 6f 77 65 76 65 72 2c 20 6d 6f 72 65 20 63 6f |However, more co| 00000e90 6d 70 6c 65 78 20 70 72 6f 67 72 61 6d 73 20 6d |mplex programs m| 00000ea0 61 79 2c 20 66 6f 72 20 65 78 61 6d 70 6c 65 2c |ay, for example,| 00000eb0 20 73 65 74 20 61 0d 70 61 67 65 20 67 72 61 62 | set a.page grab| 00000ec0 62 65 72 20 66 72 6f 6d 20 72 65 63 65 69 76 65 |ber from receive| 00000ed0 64 20 69 6e 66 6f 72 6d 61 74 69 6f 6e 20 73 75 |d information su| 00000ee0 63 68 20 61 73 20 74 68 65 20 70 61 67 65 20 6c |ch as the page l| 00000ef0 69 6e 6b 20 73 65 74 74 69 6e 67 73 2c 20 61 6e |ink settings, an| 00000f00 64 0d 61 20 73 63 61 6e 20 6f 66 20 74 68 65 20 |d.a scan of the | 00000f10 63 75 72 72 65 6e 74 20 67 72 61 62 62 65 72 20 |current grabber | 00000f20 64 65 74 61 69 6c 73 20 63 6f 75 6c 64 20 64 65 |details could de| 00000f30 74 65 72 6d 69 6e 65 20 77 68 65 74 68 65 72 20 |termine whether | 00000f40 61 6e 6f 74 68 65 72 20 70 61 67 65 0d 67 72 61 |another page.gra| 00000f50 62 62 65 72 20 68 61 73 20 61 6c 72 65 61 64 79 |bber has already| 00000f60 20 62 65 65 6e 20 73 65 74 20 74 6f 20 72 65 63 | been set to rec| 00000f70 65 69 76 65 20 74 68 65 20 70 61 67 65 2e 20 49 |eive the page. I| 00000f80 74 20 69 73 20 69 6d 70 6f 72 74 61 6e 74 20 6e |t is important n| 00000f90 6f 74 20 74 6f 0d 73 65 74 20 74 77 6f 20 70 61 |ot to.set two pa| 00000fa0 67 65 20 67 72 61 62 62 65 72 73 20 74 6f 20 72 |ge grabbers to r| 00000fb0 65 63 65 69 76 65 20 74 68 65 20 73 61 6d 65 20 |eceive the same | 00000fc0 70 61 67 65 20 61 73 20 74 68 65 20 68 69 67 68 |page as the high| 00000fd0 65 72 20 6e 75 6d 62 65 72 65 64 20 70 61 67 65 |er numbered page| 00000fe0 0d 67 72 61 62 62 65 72 20 77 69 6c 6c 20 6e 65 |.grabber will ne| 00000ff0 76 65 72 20 72 65 63 65 69 76 65 20 69 74 21 20 |ver receive it! | 00001000 28 49 74 20 69 73 20 70 6f 73 73 69 62 6c 65 20 |(It is possible | 00001010 74 6f 20 73 65 74 20 74 77 6f 20 64 69 66 66 65 |to set two diffe| 00001020 72 65 6e 74 20 70 61 67 65 0d 67 72 61 62 62 65 |rent page.grabbe| 00001030 72 73 20 74 6f 20 72 65 63 65 69 76 65 20 64 69 |rs to receive di| 00001040 66 66 65 72 65 6e 74 20 73 75 62 2d 70 61 67 65 |fferent sub-page| 00001050 73 20 66 72 6f 6d 20 74 68 65 20 73 61 6d 65 20 |s from the same | 00001060 70 61 67 65 2c 20 68 6f 77 65 76 65 72 2e 29 0d |page, however.).| 00001070 0d 52 65 61 64 20 61 20 72 65 63 6f 72 64 20 66 |.Read a record f| 00001080 6c 61 67 3a 0d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |lag:.===========| 00001090 3d 3d 3d 3d 3d 3d 3d 3d 0d 54 68 65 20 22 72 65 |========.The "re| 000010a0 63 6f 72 64 20 66 6c 61 67 22 20 67 69 76 65 73 |cord flag" gives| 000010b0 20 69 6d 70 6f 72 74 61 6e 74 20 69 6e 66 6f 72 | important infor| 000010c0 6d 61 74 69 6f 6e 20 61 62 6f 75 74 20 74 68 65 |mation about the| 000010d0 20 63 75 72 72 65 6e 74 20 73 74 61 74 75 73 20 | current status | 000010e0 6f 66 0d 74 68 65 20 70 61 72 74 69 63 75 6c 61 |of.the particula| 000010f0 72 20 70 61 67 65 20 67 72 61 62 62 65 72 20 2d |r page grabber -| 00001100 20 77 68 65 74 68 65 72 20 74 68 65 20 70 61 67 | whether the pag| 00001110 65 20 69 73 20 62 65 69 6e 67 20 72 65 63 65 69 |e is being recei| 00001120 76 65 64 20 61 74 20 74 68 65 0d 6d 6f 6d 65 6e |ved at the.momen| 00001130 74 20 74 68 65 20 63 61 6c 6c 20 69 73 20 6d 61 |t the call is ma| 00001140 64 65 2c 20 77 68 65 74 68 65 72 20 69 74 20 68 |de, whether it h| 00001150 61 73 20 62 65 65 6e 20 70 72 65 76 69 6f 75 73 |as been previous| 00001160 6c 79 20 72 65 63 65 69 76 65 64 2c 20 6f 72 0d |ly received, or.| 00001170 77 68 65 74 68 65 72 20 69 74 20 69 73 20 22 6f |whether it is "o| 00001180 6e 20 68 6f 6c 64 22 2e 0d 0d 53 65 74 20 61 20 |n hold"...Set a | 00001190 72 65 63 6f 72 64 20 66 6c 61 67 3a 0d 3d 3d 3d |record flag:.===| 000011a0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0d |===============.| 000011b0 54 68 69 73 20 61 6c 6c 6f 77 73 20 75 73 20 74 |This allows us t| 000011c0 6f 20 70 75 74 20 61 20 73 70 65 63 69 66 69 63 |o put a specific| 000011d0 20 70 61 67 65 20 67 72 61 62 62 65 72 20 6f 6e | page grabber on| 000011e0 20 68 6f 6c 64 20 28 69 2e 65 2e 20 74 6f 20 70 | hold (i.e. to p| 000011f0 72 65 76 65 6e 74 20 74 68 65 0d 70 61 67 65 20 |revent the.page | 00001200 62 65 69 6e 67 20 6f 76 65 72 77 72 69 74 74 65 |being overwritte| 00001210 6e 20 62 79 20 61 6e 79 20 73 75 62 73 65 71 75 |n by any subsequ| 00001220 65 6e 74 6c 79 20 72 65 63 65 69 76 65 64 20 76 |ently received v| 00001230 65 72 73 69 6f 6e 73 29 20 6f 72 20 74 6f 0d 72 |ersions) or to.r| 00001240 65 6c 65 61 73 65 20 69 74 20 28 73 6f 20 73 75 |elease it (so su| 00001250 62 73 65 71 75 65 6e 74 20 70 61 67 65 20 72 65 |bsequent page re| 00001260 63 65 70 74 69 6f 6e 20 6f 76 65 72 77 72 69 74 |ception overwrit| 00001270 65 73 20 74 68 65 20 70 72 65 76 69 6f 75 73 20 |es the previous | 00001280 76 65 72 73 69 6f 6e 29 2e 0d 0d 43 6c 65 61 72 |version)...Clear| 00001290 20 61 6c 6c 20 70 61 67 65 20 67 72 61 62 62 65 | all page grabbe| 000012a0 72 20 72 65 63 6f 72 64 73 3a 0d 3d 3d 3d 3d 3d |r records:.=====| 000012b0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 000012c0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0d 55 73 65 64 20 |==========.Used | 000012d0 74 6f 20 72 65 73 65 74 20 61 6c 6c 20 74 68 65 |to reset all the| 000012e0 20 70 61 67 65 20 67 72 61 62 62 65 72 73 20 73 | page grabbers s| 000012f0 6f 20 74 68 65 79 20 61 72 65 20 6e 6f 20 6c 6f |o they are no lo| 00001300 6e 67 65 72 20 73 65 61 72 63 68 69 6e 67 20 66 |nger searching f| 00001310 6f 72 0d 43 45 45 46 41 58 20 70 61 67 65 73 2e |or.CEEFAX pages.| 00001320 20 54 6f 20 63 6c 65 61 72 20 61 20 73 69 6e 67 | To clear a sing| 00001330 6c 65 20 70 61 67 65 20 67 72 61 62 62 65 72 20 |le page grabber | 00001340 69 73 20 6e 6f 74 20 70 6f 73 73 69 62 6c 65 2c |is not possible,| 00001350 20 62 75 74 20 74 68 65 20 73 61 6d 65 0d 0d 0d | but the same...| 00001360 0d 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |.. | 00001370 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00001380 20 20 20 20 50 61 67 65 20 32 0d 0d 0d 0d 0d 0d | Page 2......| 00001390 0d 0d 0d 49 6e 74 65 72 61 63 74 69 76 65 20 70 |...Interactive p| 000013a0 72 6f 67 72 61 6d 6d 69 6e 67 20 20 20 20 20 20 |rogramming | 000013b0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000013c0 20 20 20 20 20 20 20 20 20 20 20 20 4a 2e 4a 2e | J.J.| 000013d0 42 72 61 79 73 68 61 77 20 31 39 38 37 0d 0d 0d |Brayshaw 1987...| 000013e0 0d 0d 65 66 66 65 63 74 20 63 61 6e 20 62 65 20 |..effect can be | 000013f0 61 63 68 69 65 76 65 64 20 62 79 20 70 75 74 74 |achieved by putt| 00001400 69 6e 67 20 74 68 65 20 61 70 70 72 6f 70 72 69 |ing the appropri| 00001410 61 74 65 20 67 72 61 62 62 65 72 20 6f 6e 20 22 |ate grabber on "| 00001420 68 6f 6c 64 22 2e 20 50 61 67 65 0d 67 72 61 62 |hold". Page.grab| 00001430 62 65 72 73 20 63 61 6e 20 62 65 20 72 65 2d 73 |bers can be re-s| 00001440 65 74 20 74 6f 20 72 65 63 65 69 76 65 20 61 20 |et to receive a | 00001450 64 69 66 66 65 72 65 6e 74 20 70 61 67 65 20 77 |different page w| 00001460 69 74 68 6f 75 74 20 68 61 76 69 6e 67 20 74 6f |ithout having to| 00001470 20 62 65 0d 64 69 73 61 62 6c 65 64 20 66 69 72 | be.disabled fir| 00001480 73 74 2e 0d 0d 4f 6e 63 65 20 65 6e 67 61 67 65 |st...Once engage| 00001490 64 2c 20 61 20 70 61 67 65 20 67 72 61 62 62 65 |d, a page grabbe| 000014a0 72 20 63 6f 6e 74 69 6e 75 65 73 20 74 6f 20 72 |r continues to r| 000014b0 65 63 65 69 76 65 20 74 68 65 20 72 65 71 75 65 |eceive the reque| 000014c0 73 74 65 64 20 70 61 67 65 20 75 6e 74 69 6c 0d |sted page until.| 000014d0 63 61 6e 63 65 6c 6c 65 64 2e 20 41 73 20 74 68 |cancelled. As th| 000014e0 69 73 20 69 73 20 61 6e 20 22 69 6e 74 65 72 72 |is is an "interr| 000014f0 75 70 74 22 20 70 72 6f 63 65 73 73 2c 20 69 74 |upt" process, it| 00001500 20 77 69 6c 6c 20 63 6f 6e 74 69 6e 75 65 20 74 | will continue t| 00001510 6f 20 72 65 63 65 69 76 65 0d 61 6e 64 20 74 72 |o receive.and tr| 00001520 61 6e 73 66 65 72 20 70 61 67 65 73 20 65 76 65 |ansfer pages eve| 00001530 6e 20 61 66 74 65 72 20 74 68 65 20 70 72 6f 67 |n after the prog| 00001540 72 61 6d 20 65 6e 64 73 21 20 49 74 20 69 73 2c |ram ends! It is,| 00001550 20 74 68 65 72 65 66 6f 72 65 2c 20 76 65 72 79 | therefore, very| 00001560 0d 69 6d 70 6f 72 74 61 6e 74 20 74 6f 20 74 75 |.important to tu| 00001570 72 6e 20 6f 66 66 20 74 68 65 20 70 61 67 65 20 |rn off the page | 00001580 67 72 61 62 62 65 72 73 20 62 65 66 6f 72 65 20 |grabbers before | 00001590 6c 65 61 76 69 6e 67 20 74 68 65 20 70 72 6f 67 |leaving the prog| 000015a0 72 61 6d 2e 0d 2a 54 54 58 4f 46 46 20 77 69 6c |ram..*TTXOFF wil| 000015b0 6c 20 61 63 68 69 65 76 65 20 74 68 69 73 2c 20 |l achieve this, | 000015c0 62 75 74 20 69 73 20 61 20 64 72 61 73 74 69 63 |but is a drastic| 000015d0 20 61 6e 64 20 6e 6f 74 20 76 65 72 79 20 65 6c | and not very el| 000015e0 65 67 61 6e 74 20 6d 65 74 68 6f 64 0d 28 72 61 |egant method.(ra| 000015f0 74 68 65 72 20 6c 69 6b 65 20 42 52 45 41 4b 20 |ther like BREAK | 00001600 69 73 20 74 6f 20 61 20 42 41 53 49 43 20 70 72 |is to a BASIC pr| 00001610 6f 67 72 61 6d 29 2e 20 41 6e 20 41 54 53 20 4f |ogram). An ATS O| 00001620 53 57 4f 52 44 20 63 61 6c 6c 20 69 73 20 70 72 |SWORD call is pr| 00001630 6f 76 69 64 65 64 0d 74 6f 20 73 74 6f 70 20 74 |ovided.to stop t| 00001640 68 65 20 70 61 67 65 20 67 72 61 62 62 65 72 73 |he page grabbers| 00001650 20 72 65 63 65 69 76 69 6e 67 20 70 61 67 65 73 | receiving pages| 00001660 2e 0d 0d 41 6e 79 20 61 74 74 65 6d 70 74 20 74 |...Any attempt t| 00001670 6f 20 61 6c 74 65 72 20 6f 72 20 72 65 73 65 74 |o alter or reset| 00001680 20 61 20 70 61 67 65 20 67 72 61 62 62 65 72 20 | a page grabber | 00001690 64 75 72 69 6e 67 20 74 68 65 20 61 63 74 75 61 |during the actua| 000016a0 6c 20 72 65 63 65 70 74 69 6f 6e 0d 6f 66 20 61 |l reception.of a| 000016b0 20 70 61 67 65 20 73 68 6f 75 6c 64 20 62 65 20 | page should be | 000016c0 61 76 6f 69 64 65 64 2e 20 54 68 65 20 70 72 6f |avoided. The pro| 000016d0 67 72 61 6d 20 42 2f 41 54 53 31 32 20 63 61 72 |gram B/ATS12 car| 000016e0 72 69 65 73 20 6f 75 74 20 73 65 76 65 72 61 6c |ries out several| 000016f0 0d 70 72 6f 63 65 73 73 65 73 20 62 65 66 6f 72 |.processes befor| 00001700 65 20 64 69 73 61 62 6c 69 6e 67 20 74 68 65 20 |e disabling the | 00001710 70 61 67 65 20 67 72 61 62 62 65 72 73 3a 0d 0d |page grabbers:..| 00001720 28 31 29 20 45 61 63 68 20 70 61 67 65 20 67 72 |(1) Each page gr| 00001730 61 62 62 65 72 20 69 73 20 69 6e 74 65 72 72 6f |abber is interro| 00001740 67 61 74 65 64 20 74 6f 20 65 6e 73 75 72 65 20 |gated to ensure | 00001750 61 20 70 61 67 65 20 68 61 73 20 61 63 74 75 61 |a page has actua| 00001760 6c 6c 79 20 62 65 65 6e 0d 72 65 63 65 69 76 65 |lly been.receive| 00001770 64 2e 20 54 68 65 20 4f 53 57 4f 52 44 20 63 61 |d. The OSWORD ca| 00001780 6c 6c 20 74 6f 20 73 65 74 20 61 20 70 61 67 65 |ll to set a page| 00001790 20 67 72 61 62 62 65 72 20 72 65 74 75 72 6e 73 | grabber returns| 000017a0 20 63 6f 6e 74 72 6f 6c 20 74 6f 20 79 6f 75 72 | control to your| 000017b0 0d 70 72 6f 67 72 61 6d 20 69 6d 6d 65 64 69 61 |.program immedia| 000017c0 74 65 6c 79 2c 20 61 6e 64 2c 20 75 6e 6c 69 6b |tely, and, unlik| 000017d0 65 20 74 68 65 20 2a 54 52 41 4e 53 46 45 52 20 |e the *TRANSFER | 000017e0 63 6f 6d 6d 61 6e 64 2c 20 64 6f 65 73 20 6e 6f |command, does no| 000017f0 74 20 77 61 69 74 0d 75 6e 74 69 6c 20 61 20 70 |t wait.until a p| 00001800 61 67 65 20 68 61 73 20 62 65 65 6e 20 72 65 63 |age has been rec| 00001810 65 69 76 65 64 2e 20 49 74 20 69 73 20 74 68 65 |eived. 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It offers | 00001cd0 6e 75 6d 65 72 6f 75 73 20 61 64 76 61 6e 74 61 |numerous advanta| 00001ce0 67 65 73 3a 0d 0d 20 2d 20 20 74 68 65 20 70 61 |ges:.. - the pa| 00001cf0 67 65 20 69 73 20 6b 65 70 74 20 75 70 2d 74 6f |ge is kept up-to| 00001d00 2d 64 61 74 65 20 61 74 20 61 6c 6c 20 74 69 6d |-date at all tim| 00001d10 65 73 20 77 69 74 68 6f 75 74 20 66 75 72 74 68 |es without furth| 00001d20 65 72 20 69 6e 74 65 72 76 65 6e 74 69 6f 6e 2e |er intervention.| 00001d30 0d 20 20 20 20 28 54 72 79 20 61 64 6a 75 73 74 |. (Try adjust| 00001d40 69 6e 67 20 74 68 65 20 70 72 6f 67 72 61 6d 20 |ing the program | 00001d50 73 6f 20 79 6f 75 20 65 6e 74 65 72 20 56 69 64 |so you enter Vid| 00001d60 69 45 64 20 69 6d 6d 65 64 69 61 74 65 6c 79 20 |iEd immediately | 00001d70 61 66 74 65 72 0d 0d 0d 0d 0d 20 20 20 20 20 20 |after..... | 00001d80 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00001d90 20 20 20 20 20 20 20 20 20 20 20 20 50 61 67 65 | Page| 00001da0 20 33 0d 0d 0d 0d 0d 0d 0d 0d 0d 49 6e 74 65 72 | 3.........Inter| 00001db0 61 63 74 69 76 65 20 70 72 6f 67 72 61 6d 6d 69 |active programmi| 00001dc0 6e 67 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |ng | 00001dd0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00001de0 20 20 20 20 4a 2e 4a 2e 42 72 61 79 73 68 61 77 | J.J.Brayshaw| 00001df0 20 31 39 38 37 0d 0d 0d 0d 0d 20 20 20 20 73 65 | 1987..... se| 00001e00 74 74 69 6e 67 20 74 68 65 20 70 61 67 65 20 67 |tting the page g| 00001e10 72 61 62 62 65 72 73 2e 20 54 68 69 73 20 77 69 |rabbers. 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Using *| 00001f00 54 52 41 4e 53 46 45 52 20 6f 72 20 2a 44 41 54 |TRANSFER or *DAT| 00001f10 41 20 68 61 6c 74 73 20 74 68 65 20 70 72 6f 67 |A halts the prog| 00001f20 72 61 6d 20 75 6e 74 69 6c 20 74 68 65 0d 20 20 |ram until the. | 00001f30 20 20 70 61 67 65 20 68 61 73 20 62 65 65 6e 20 | page has been | 00001f40 72 65 63 65 69 76 65 64 2e 0d 0d 20 2d 20 20 69 |received... - i| 00001f50 74 20 62 65 63 6f 6d 65 73 20 70 6f 73 73 69 62 |t becomes possib| 00001f60 6c 65 20 74 6f 20 64 65 74 65 72 6d 69 6e 65 20 |le to determine | 00001f70 77 68 65 74 68 65 72 20 61 20 70 61 67 65 20 69 |whether a page i| 00001f80 73 20 61 63 74 75 61 6c 6c 79 20 62 65 69 6e 67 |s actually being| 00001f90 0d 20 20 20 20 62 72 6f 61 64 63 61 73 74 20 6f |. broadcast o| 00001fa0 72 20 6e 6f 74 2e 20 54 68 65 20 74 69 6d 65 20 |r not. 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When a p| 00002520 61 67 65 20 69 73 0d 72 65 71 75 65 73 74 65 64 |age is.requested| 00002530 2c 20 69 74 20 61 63 74 69 76 61 74 65 73 20 70 |, it activates p| 00002540 61 67 65 20 67 72 61 62 62 65 72 20 7a 65 72 6f |age grabber zero| 00002550 2e 20 57 68 65 6e 20 69 74 20 69 73 20 72 65 63 |. When it is rec| 00002560 65 69 76 65 64 2c 20 74 68 65 20 6c 69 6e 6b 73 |eived, the links| 00002570 0d 61 72 65 20 64 65 63 6f 64 65 64 20 61 6e 64 |.are decoded and| 00002580 20 70 61 67 65 20 67 72 61 62 62 65 72 73 20 31 | page grabbers 1| 00002590 20 74 6f 20 34 20 61 72 65 20 73 65 74 20 74 6f | to 4 are set to| 000025a0 20 72 65 63 65 69 76 65 20 74 68 65 20 70 61 67 | receive the pag| 000025b0 65 73 20 70 6f 69 6e 74 65 64 0d 74 6f 20 62 79 |es pointed.to by| 000025c0 20 74 68 65 20 66 69 72 73 74 20 66 6f 75 72 20 | the first four | 000025d0 6c 69 6e 6b 73 2e 20 4c 69 6e 6b 20 35 20 28 74 |links. Link 5 (t| 000025e0 68 65 20 73 69 78 74 68 20 6c 69 6e 6b 29 20 69 |he sixth link) i| 000025f0 73 20 74 68 65 20 22 49 6e 64 65 78 22 20 70 61 |s the "Index" pa| 00002600 67 65 0d 77 68 69 63 68 20 69 73 20 61 6c 6c 6f |ge.which is allo| 00002610 63 61 74 65 64 20 74 6f 20 74 68 65 20 6e 65 78 |cated to the nex| 00002620 74 20 70 61 67 65 20 67 72 61 62 62 65 72 2e 20 |t page grabber. | 00002630 41 73 20 6d 61 6e 79 20 6f 66 20 74 68 65 20 72 |As many of the r| 00002640 65 6d 61 69 6e 69 6e 67 20 70 61 67 65 0d 67 72 |emaining page.gr| 00002650 61 62 62 65 72 73 20 61 73 20 70 6f 73 73 69 62 |abbers as possib| 00002660 6c 65 20 28 64 65 70 65 6e 64 69 6e 67 20 6f 6e |le (depending on| 00002670 20 74 68 65 20 61 76 61 69 6c 61 62 6c 65 20 6d | the available m| 00002680 65 6d 6f 72 79 29 20 61 72 65 20 73 65 74 20 74 |emory) are set t| 00002690 6f 0d 72 65 63 65 69 76 65 20 61 6e 79 20 75 73 |o.receive any us| 000026a0 65 72 2d 72 65 71 75 65 73 74 65 64 20 70 61 67 |er-requested pag| 000026b0 65 73 2c 20 61 73 20 69 6e 64 69 63 61 74 65 64 |es, as indicated| 000026c0 20 62 79 20 74 68 65 20 22 6b 65 65 70 20 70 61 | by the "keep pa| 000026d0 67 65 22 0d 66 61 63 69 6c 69 74 79 2e 20 49 6e |ge".facility. In| 000026e0 20 74 68 69 73 20 77 61 79 2c 20 61 6c 6c 20 74 | this way, all t| 000026f0 68 65 73 65 20 70 61 67 65 73 20 73 68 6f 75 6c |hese pages shoul| 00002700 64 20 62 65 20 72 65 61 64 79 20 66 6f 72 20 69 |d be ready for i| 00002710 6d 6d 65 64 69 61 74 65 0d 64 69 73 70 6c 61 79 |mmediate.display| 00002720 20 69 66 20 72 65 71 75 65 73 74 65 64 2e 20 45 | if requested. E| 00002730 61 63 68 20 70 61 67 65 20 73 74 6f 72 65 64 20 |ach page stored | 00002740 62 79 20 74 68 65 20 41 54 53 20 6d 75 73 74 20 |by the ATS must | 00002750 69 6e 63 6c 75 64 65 20 74 68 65 20 66 75 6c 6c |include the full| 00002760 0d 70 61 67 65 20 64 61 74 61 20 28 69 2e 65 2e |.page data (i.e.| 00002770 61 73 20 6d 61 6e 79 20 70 61 63 6b 65 74 73 20 |as many packets | 00002780 61 73 20 61 72 65 20 74 72 61 6e 73 6d 69 74 74 |as are transmitt| 00002790 65 64 29 20 61 6e 64 20 74 68 65 72 65 66 6f 72 |ed) and therefor| 000027a0 65 20 61 74 20 6c 65 61 73 74 0d 32 6b 20 6f 66 |e at least.2k of| 000027b0 20 6d 65 6d 6f 72 79 20 6d 75 73 74 20 62 65 20 | memory must be | 000027c0 61 76 61 69 6c 61 62 6c 65 20 66 6f 72 20 65 61 |available for ea| 000027d0 63 68 20 70 61 67 65 20 73 74 6f 72 65 64 20 69 |ch page stored i| 000027e0 6e 20 74 68 69 73 20 77 61 79 2e 0d 0d 2a 4e 4f |n this way...*NO| 000027f0 54 45 3a 20 53 6f 6d 65 20 6d 61 6b 65 73 20 6f |TE: Some makes o| 00002800 66 20 74 65 6c 65 74 65 78 74 20 61 64 61 70 74 |f teletext adapt| 00002810 65 72 20 75 73 65 20 6e 65 77 65 72 2c 20 62 75 |er use newer, bu| 00002820 74 20 6c 65 73 73 20 76 65 72 73 61 74 69 6c 65 |t less versatile| 00002830 2c 0d 74 65 6c 65 74 65 78 74 20 72 65 63 65 70 |,.teletext recep| 00002840 74 69 6f 6e 20 6d 69 63 72 6f 2d 63 68 69 70 73 |tion micro-chips| 00002850 2e 20 42 65 63 61 75 73 65 20 6f 66 20 74 68 65 |. Because of the| 00002860 20 6d 6f 72 65 20 6c 69 6d 69 74 65 64 20 63 6f | more limited co| 00002870 6e 74 72 6f 6c 20 74 68 65 73 65 0d 61 6c 6c 6f |ntrol these.allo| 00002880 77 2c 20 6f 6e 6c 79 20 6f 6e 65 20 70 61 67 65 |w, only one page| 00002890 20 67 72 61 62 62 65 72 20 63 61 6e 20 62 65 20 | grabber can be | 000028a0 75 73 65 64 2e 20 54 68 65 20 72 6f 75 74 69 6e |used. The routin| 000028b0 65 73 20 64 65 73 63 72 69 62 65 64 20 68 65 72 |es described her| 000028c0 65 20 61 72 65 0d 6e 6f 74 20 69 6d 70 6c 65 6d |e are.not implem| 000028d0 65 6e 74 65 64 20 6f 6e 20 73 75 63 68 20 61 64 |ented on such ad| 000028e0 61 70 74 65 72 73 2c 20 61 6c 74 68 6f 75 67 68 |apters, although| 000028f0 20 66 6f 72 20 74 68 65 20 73 61 6b 65 20 6f 66 | for the sake of| 00002900 20 63 6f 6d 70 61 74 69 62 69 6c 69 74 79 0d 0d | compatibility..| 00002910 0d 0d 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 |... | 00002920 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00002930 20 20 20 20 20 50 61 67 65 20 34 0d 0d 0d 0d 0d | Page 4.....| 00002940 0d 0d 0d 0d 49 6e 74 65 72 61 63 74 69 76 65 20 |....Interactive | 00002950 70 72 6f 67 72 61 6d 6d 69 6e 67 20 20 20 20 20 |programming | 00002960 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00002970 20 20 20 20 20 20 20 20 20 20 20 20 20 4a 2e 4a | J.J| 00002980 2e 42 72 61 79 73 68 61 77 20 31 39 38 37 0d 0d |.Brayshaw 1987..| 00002990 0d 0d 0d 74 68 65 69 72 20 76 65 72 73 69 6f 6e |...their version| 000029a0 20 6f 66 20 41 54 53 20 77 69 6c 6c 20 6e 6f 74 | of ATS will not| 000029b0 20 67 65 6e 65 72 61 74 65 20 61 6e 20 65 72 72 | generate an err| 000029c0 6f 72 2e 20 54 68 69 73 20 65 78 70 6c 61 69 6e |or. This explain| 000029d0 73 20 77 68 79 2c 20 77 69 74 68 0d 73 75 63 68 |s why, with.such| 000029e0 20 61 64 61 70 74 65 72 73 2c 20 74 68 65 20 46 | adapters, the F| 000029f0 4c 4f 46 20 73 79 73 74 65 6d 20 64 6f 65 73 20 |LOF system does | 00002a00 6e 6f 74 20 69 6e 73 74 61 6e 74 6c 79 20 64 69 |not instantly di| 00002a10 73 70 6c 61 79 20 61 20 6c 69 6e 6b 65 64 20 70 |splay a linked p| 00002a20 61 67 65 2c 0d 62 75 74 20 6d 65 72 65 6c 79 20 |age,.but merely | 00002a30 74 65 6c 6c 73 20 74 68 65 20 6f 6e 6c 79 20 70 |tells the only p| 00002a40 61 67 65 20 67 72 61 62 62 65 72 20 61 76 61 69 |age grabber avai| 00002a50 6c 61 62 6c 65 20 74 6f 20 67 65 74 20 74 68 65 |lable to get the| 00002a60 20 6c 69 6e 6b 65 64 20 70 61 67 65 0d 75 70 6f | linked page.upo| 00002a70 6e 20 69 74 73 20 6e 65 78 74 20 62 72 6f 61 64 |n its next broad| 00002a80 63 61 73 74 2e 0d 0d 55 73 69 6e 67 20 74 68 65 |cast...Using the| 00002a90 20 70 61 67 65 20 67 72 61 62 62 65 72 73 20 69 | page grabbers i| 00002aa0 6e 63 6c 75 64 65 64 20 77 69 74 68 20 41 54 53 |ncluded with ATS| 00002ab0 20 61 6e 64 20 74 68 65 20 41 63 6f 72 6e 20 61 | and the Acorn a| 00002ac0 64 61 70 74 65 72 20 72 65 6d 6f 76 65 73 0d 74 |dapter removes.t| 00002ad0 68 65 20 6c 69 6d 69 74 61 74 69 6f 6e 73 20 69 |he limitations i| 00002ae0 6d 70 6f 73 65 64 20 62 79 20 74 68 65 20 73 69 |mposed by the si| 00002af0 6e 67 6c 65 2d 70 61 67 65 20 74 72 61 6e 73 66 |ngle-page transf| 00002b00 65 72 20 63 6f 6d 6d 61 6e 64 73 20 2a 50 41 47 |er commands *PAG| 00002b10 45 2c 0d 2a 54 52 41 4e 53 46 45 52 20 61 6e 64 |E,.*TRANSFER and| 00002b20 20 2a 44 41 54 41 2e 20 4e 6f 74 20 61 6c 6c 20 | *DATA. Not all | 00002b30 32 30 20 67 72 61 62 62 65 72 73 20 68 61 76 65 |20 grabbers have| 00002b40 20 74 6f 20 62 65 20 73 65 74 20 2d 20 79 6f 75 | to be set - you| 00002b50 20 63 61 6e 20 75 73 65 20 61 6e 79 0d 71 75 61 | can use any.qua| 00002b60 6e 74 69 74 79 20 66 72 6f 6d 20 31 20 74 6f 20 |ntity from 1 to | 00002b70 32 30 20 2d 20 77 68 69 63 68 20 6d 65 61 6e 73 |20 - which means| 00002b80 20 61 6c 6d 6f 73 74 20 61 6e 79 20 74 65 6c 65 | almost any tele| 00002b90 74 65 78 74 20 61 70 70 6c 69 63 61 74 69 6f 6e |text application| 00002ba0 20 63 61 6e 20 62 65 0d 69 6d 70 72 6f 76 65 64 | can be.improved| 00002bb0 20 61 6e 64 20 73 70 65 65 64 65 64 20 75 70 20 | and speeded up | 00002bc0 62 79 20 75 73 69 6e 67 20 74 68 69 73 20 6d 65 |by using this me| 00002bd0 74 68 6f 64 20 6f 66 20 70 61 67 65 20 72 65 63 |thod of page rec| 00002be0 65 70 74 69 6f 6e 2e 0d 0d 5f 5f 5f 5f 5f 5f 5f |eption..._______| 00002bf0 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f 5f |________________| * 00002c30 5f 5f 5f 0d 0d 42 2f 41 54 53 31 32 20 77 69 6c |___..B/ATS12 wil| 00002c40 6c 20 63 61 70 74 75 72 65 20 65 61 63 68 20 6f |l capture each o| 00002c50 66 20 74 68 65 20 6e 65 77 73 20 70 61 67 65 73 |f the news pages| 00002c60 20 62 72 6f 61 64 63 61 73 74 20 62 79 20 43 45 | broadcast by CE| 00002c70 45 46 41 58 2c 20 61 73 20 77 65 6c 6c 0d 61 73 |EFAX, as well.as| 00002c80 20 74 68 65 20 6d 61 69 6e 20 69 6e 64 65 78 20 | the main index | 00002c90 70 61 67 65 2c 20 74 68 65 20 66 69 6e 61 6e 63 |page, the financ| 00002ca0 69 61 6c 20 69 6e 64 65 78 20 70 61 67 65 20 61 |ial index page a| 00002cb0 6e 64 20 74 68 65 20 6e 65 77 73 20 69 6e 64 65 |nd the news inde| 00002cc0 78 20 70 61 67 65 2e 0d 49 74 20 73 65 74 73 20 |x page..It sets | 00002cd0 61 6c 6c 20 32 30 20 70 61 67 65 20 67 72 61 62 |all 20 page grab| 00002ce0 62 65 72 73 20 74 68 65 6e 20 77 61 69 74 73 20 |bers then waits | 00002cf0 75 6e 74 69 6c 20 65 61 63 68 20 67 72 61 62 62 |until each grabb| 00002d00 65 72 20 69 6e 64 69 63 61 74 65 73 20 69 74 0d |er indicates it.| 00002d10 68 61 73 20 63 61 70 74 75 72 65 64 20 61 20 70 |has captured a p| 00002d20 61 67 65 2e 20 28 44 75 72 69 6e 67 20 74 68 69 |age. (During thi| 00002d30 73 20 74 69 6d 65 2c 20 74 68 65 20 70 72 6f 67 |s time, the prog| 00002d40 72 61 6d 20 63 6f 75 6c 64 20 62 65 20 6d 61 64 |ram could be mad| 00002d50 65 20 74 6f 20 64 6f 0d 6f 74 68 65 72 20 74 68 |e to do.other th| 00002d60 69 6e 67 73 2e 29 0d 0d 4f 6e 63 65 20 63 61 70 |ings.)..Once cap| 00002d70 74 75 72 65 64 2c 20 65 61 63 68 20 70 61 67 65 |tured, each page| 00002d80 20 67 72 61 62 62 65 64 20 63 61 6e 20 62 65 20 | grabbed can be | 00002d90 64 69 73 70 6c 61 79 65 64 2e 20 54 68 65 20 70 |displayed. The p| 00002da0 61 67 65 20 63 61 70 74 75 72 65 64 20 62 79 0d |age captured by.| 00002db0 74 68 65 20 66 69 72 73 74 20 70 61 67 65 20 67 |the first page g| 00002dc0 72 61 62 62 65 72 20 69 73 20 73 68 65 77 6e 2e |rabber is shewn.| 00002dd0 20 28 72 65 63 6f 72 64 20 6e 75 6d 62 65 72 20 | (record number | 00002de0 7a 65 72 6f 29 2e 20 42 79 20 70 72 65 73 73 69 |zero). By pressi| 00002df0 6e 67 20 74 68 65 0d 6c 65 66 74 20 6f 72 20 72 |ng the.left or r| 00002e00 69 67 68 74 20 61 72 72 6f 77 20 6b 65 79 2c 20 |ight arrow key, | 00002e10 61 6c 6c 20 74 68 65 20 70 61 67 65 73 20 69 6e |all the pages in| 00002e20 20 74 68 65 20 73 65 71 75 65 6e 63 65 20 63 61 | the sequence ca| 00002e30 6e 20 62 65 20 73 65 65 6e 2e 20 54 6f 0d 70 72 |n be seen. To.pr| 00002e40 6f 76 65 20 74 68 65 20 67 72 61 62 62 65 72 73 |ove the grabbers| 00002e50 20 61 72 65 20 73 74 69 6c 6c 20 61 63 74 69 76 | are still activ| 00002e60 65 2c 20 74 72 79 20 66 69 6e 64 69 6e 67 20 61 |e, try finding a| 00002e70 20 70 61 67 65 20 77 69 74 68 20 6d 6f 72 65 20 | page with more | 00002e80 74 68 61 6e 20 6f 6e 65 0d 73 75 62 2d 70 61 67 |than one.sub-pag| 00002e90 65 2e 20 54 68 65 20 70 61 67 65 20 67 72 61 62 |e. The page grab| 00002ea0 62 65 72 20 69 73 20 73 65 74 20 74 6f 20 75 70 |ber is set to up| 00002eb0 64 61 74 65 20 74 68 65 20 70 61 67 65 20 69 6e |date the page in| 00002ec0 20 6d 65 6d 6f 72 79 2c 20 6e 6f 74 20 6f 6e 20 | memory, not on | 00002ed0 74 68 65 0d 73 63 72 65 65 6e 2c 20 73 6f 20 74 |the.screen, so t| 00002ee0 6f 20 73 65 65 20 61 6e 79 20 63 68 61 6e 67 65 |o see any change| 00002ef0 20 69 6e 20 74 68 65 20 70 61 67 65 20 79 6f 75 | in the page you| 00002f00 20 77 69 6c 6c 20 6e 65 65 64 20 74 6f 20 6d 6f | will need to mo| 00002f10 76 65 20 74 6f 20 61 6e 6f 74 68 65 72 0d 70 61 |ve to another.pa| 00002f20 67 65 20 61 6e 64 20 62 61 63 6b 20 61 67 61 69 |ge and back agai| 00002f30 6e 21 0d 0d 59 6f 75 20 63 61 6e 20 63 79 63 6c |n!..You can cycl| 00002f40 65 20 74 68 72 6f 75 67 68 20 74 68 65 20 70 61 |e through the pa| 00002f50 67 65 73 20 61 74 20 77 69 6c 6c 2c 20 75 73 69 |ges at will, usi| 00002f60 6e 67 20 74 68 65 20 6c 65 66 74 20 61 72 72 6f |ng the left arro| 00002f70 77 20 74 6f 20 6d 6f 76 65 20 64 6f 77 6e 0d 74 |w to move down.t| 00002f80 68 65 20 73 65 71 75 65 6e 63 65 2c 20 61 6e 64 |he sequence, and| 00002f90 20 74 68 65 20 72 69 67 68 74 20 61 72 72 6f 77 | the right arrow| 00002fa0 20 74 6f 20 6d 6f 76 65 20 75 70 2e 0d 0d 55 70 | to move up...Up| 00002fb0 6f 6e 20 70 72 65 73 73 69 6e 67 20 74 68 65 20 |on pressing the | 00002fc0 53 50 41 43 45 20 42 41 52 2c 20 74 68 65 20 70 |SPACE BAR, the p| 00002fd0 72 6f 67 72 61 6d 20 63 61 72 72 69 65 73 20 6f |rogram carries o| 00002fe0 75 74 20 74 68 65 20 73 65 71 75 65 6e 63 65 20 |ut the sequence | 00002ff0 6f 66 0d 6f 70 65 72 61 74 69 6f 6e 73 20 64 65 |of.operations de| 00003000 73 63 72 69 62 65 64 20 61 62 6f 76 65 20 74 6f |scribed above to| 00003010 20 64 69 73 61 62 6c 65 20 74 68 65 20 70 61 67 | disable the pag| 00003020 65 20 67 72 61 62 62 65 72 73 2e 20 4f 6e 63 65 |e grabbers. Once| 00003030 20 74 68 69 73 20 68 61 73 0d 62 65 65 6e 20 64 | this has.been d| 00003040 6f 6e 65 2c 20 65 61 63 68 20 70 61 67 65 20 69 |one, each page i| 00003050 73 20 67 69 76 65 6e 20 61 20 73 75 69 74 61 62 |s given a suitab| 00003060 6c 65 20 68 65 61 64 65 72 20 61 6e 64 20 61 6c |le header and al| 00003070 6c 20 74 68 65 20 72 65 63 6f 72 64 73 20 61 72 |l the records ar| 00003080 65 0d 73 61 76 65 64 20 61 73 20 61 20 73 69 6e |e.saved as a sin| 00003090 67 6c 65 20 56 69 64 69 45 64 20 6d 61 67 61 7a |gle VidiEd magaz| 000030a0 69 6e 65 2e 20 49 66 20 79 6f 75 20 6e 6f 77 20 |ine. If you now | 000030b0 65 6e 74 65 72 20 56 69 64 69 45 64 20 61 6e 64 |enter VidiEd and| 000030c0 20 72 65 2d 6c 6f 61 64 20 74 68 65 0d 6d 61 67 | re-load the.mag| 000030d0 61 7a 69 6e 65 20 28 63 61 6c 6c 65 64 20 22 43 |azine (called "C| 000030e0 45 45 46 41 58 22 20 61 6e 64 20 73 61 76 65 64 |EEFAX" and saved| 000030f0 20 69 6e 20 74 68 65 20 22 44 22 20 64 69 72 65 | in the "D" dire| 00003100 63 74 6f 72 79 29 20 79 6f 75 20 63 61 6e 20 73 |ctory) you can s| 00003110 65 65 2c 20 62 79 0d 74 79 70 69 6e 67 20 4d 41 |ee, by.typing MA| 00003120 47 41 5a 49 4e 45 20 6f 6e 20 74 68 65 20 63 6f |GAZINE on the co| 00003130 6d 6d 61 6e 64 20 6c 69 6e 65 2c 20 74 68 65 20 |mmand line, the | 00003140 74 69 6d 65 20 65 61 63 68 20 70 61 67 65 20 77 |time each page w| 00003150 61 73 20 63 61 70 74 75 72 65 64 2e 0d 2a 44 41 |as captured..*DA| 00003160 54 41 20 6f 72 20 2a 54 52 41 4e 53 46 45 52 20 |TA or *TRANSFER | 00003170 77 6f 75 6c 64 20 68 61 76 65 20 6d 65 61 6e 74 |would have meant| 00003180 20 61 20 67 61 70 20 6f 66 20 61 72 6f 75 6e 64 | a gap of around| 00003190 20 32 30 20 73 65 63 6f 6e 64 73 20 62 65 74 77 | 20 seconds betw| 000031a0 65 65 6e 0d 72 65 63 65 70 74 69 6f 6e 20 6f 66 |een.reception of| 000031b0 20 65 61 63 68 20 70 61 67 65 20 2d 20 61 20 74 | each page - a t| 000031c0 6f 74 61 6c 20 6f 66 20 61 72 6f 75 6e 64 20 37 |otal of around 7| 000031d0 20 6d 69 6e 75 74 65 73 2e 20 42 79 20 75 73 69 | minutes. By usi| 000031e0 6e 67 20 74 68 65 20 70 61 67 65 0d 67 72 61 62 |ng the page.grab| 000031f0 62 65 72 73 20 77 65 20 63 61 6e 20 63 61 70 74 |bers we can capt| 00003200 75 72 65 20 61 6c 6c 20 32 30 20 70 61 67 65 73 |ure all 20 pages| 00003210 20 77 69 74 68 69 6e 20 61 20 73 69 6e 67 6c 65 | within a single| 00003220 20 43 45 45 46 41 58 20 63 79 63 6c 65 20 28 69 | CEEFAX cycle (i| 00003230 2e 65 2e 0d 6c 65 73 73 20 74 68 61 6e 20 32 30 |.e..less than 20| 00003240 20 73 65 63 6f 6e 64 73 20 61 6e 64 20 73 6f 6d | seconds and som| 00003250 65 74 69 6d 65 73 20 69 6e 20 61 73 20 6c 69 74 |etimes in as lit| 00003260 74 6c 65 20 61 73 20 74 77 6f 20 73 65 63 6f 6e |tle as two secon| 00003270 64 73 21 29 20 73 61 76 69 6e 67 0d 6f 76 65 72 |ds!) saving.over| 00003280 20 73 69 78 20 6d 69 6e 75 74 65 73 21 0d 0d 41 | six minutes!..A| 00003290 44 46 53 20 75 73 65 72 73 20 77 69 6c 6c 20 6e |DFS users will n| 000032a0 65 65 64 20 74 6f 20 61 64 6a 75 73 74 20 74 68 |eed to adjust th| 000032b0 65 20 66 69 6c 65 20 6e 61 6d 65 20 75 6e 64 65 |e file name unde| 000032c0 72 20 77 68 69 63 68 20 74 68 65 20 56 69 64 69 |r which the Vidi| 000032d0 45 64 0d 6d 61 67 61 7a 69 6e 65 20 69 73 20 73 |Ed.magazine is s| 000032e0 61 76 65 64 2c 20 74 6f 20 65 78 63 6c 75 64 65 |aved, to exclude| 000032f0 20 74 68 65 20 72 65 66 65 72 65 6e 63 65 20 74 | the reference t| 00003300 6f 20 74 68 65 20 22 44 22 20 64 69 72 65 63 74 |o the "D" direct| 00003310 6f 72 79 2e 20 54 68 65 0d 61 70 70 72 6f 70 72 |ory. The.appropr| 00003320 69 61 74 65 20 6c 69 6e 65 20 69 6e 20 74 68 65 |iate line in the| 00003330 20 70 72 6f 67 72 61 6d 20 69 73 20 70 72 65 63 | program is prec| 00003340 65 64 65 64 20 62 79 20 61 6e 20 69 64 65 6e 74 |eded by an ident| 00003350 69 66 79 69 6e 67 20 52 45 4d 0d 73 74 61 74 65 |ifying REM.state| 00003360 6d 65 6e 74 2e 0d 0d 49 66 20 79 6f 75 20 64 6f |ment...If you do| 00003370 20 6e 6f 74 20 68 61 76 65 20 61 20 63 6f 70 79 | not have a copy| 00003380 20 6f 66 20 74 68 65 20 56 69 64 69 45 64 20 70 | of the VidiEd p| 00003390 72 6f 67 72 61 6d 2c 20 64 6f 6e 27 74 20 77 6f |rogram, don't wo| 000033a0 72 72 79 20 2d 20 69 74 20 77 69 6c 6c 20 62 65 |rry - it will be| 000033b0 0d 0d 0d 0d 0d 20 20 20 20 20 20 20 20 20 20 20 |..... | 000033c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000033d0 20 20 20 20 20 20 20 50 61 67 65 20 35 0d 0d 0d | Page 5...| 000033e0 0d 0d 0d 0d 0d 0d 49 6e 74 65 72 61 63 74 69 76 |......Interactiv| 000033f0 65 20 70 72 6f 67 72 61 6d 6d 69 6e 67 20 20 20 |e programming | 00003400 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003410 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 4a | J| 00003420 2e 4a 2e 42 72 61 79 73 68 61 77 20 31 39 38 37 |.J.Brayshaw 1987| 00003430 0d 0d 0d 0d 0d 72 65 2d 62 72 6f 61 64 63 61 73 |.....re-broadcas| 00003440 74 20 6e 65 78 74 20 77 65 65 6b 2e 20 49 6e 20 |t next week. In | 00003450 74 68 65 20 6d 65 61 6e 74 69 6d 65 2c 20 68 61 |the meantime, ha| 00003460 76 65 20 66 75 6e 20 67 72 61 62 62 69 6e 67 20 |ve fun grabbing | 00003470 43 45 45 46 41 58 20 62 79 20 74 68 65 0d 73 63 |CEEFAX by the.sc| 00003480 6f 72 65 21 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d |ore!............| 00003490 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d 0d |................| * 000034b0 0d 0d 0d 0d 0d 0d 0d 20 20 20 20 20 20 20 20 20 |....... | 000034c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000034d0 20 20 20 20 20 20 20 20 20 50 61 67 65 20 36 0d | Page 6.| 000034e0 0d 0d 0d 0d |....| 000034e4
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