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26-08-88/T\DFS03
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.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » CEEFAX disks » telesoftware9.adl |
| Filename: | 26-08-88/T\DFS03 |
| Read OK: | ✔ |
| File size: | 4102 bytes |
| Load address: | 0000 |
| Exec address: | FFFFFFFF |
File contents
The Acorn DFS Osword commands - by - Gordon Horsington
----------------------------------------------------------
Module 3. Formatting single density discs
-----------------------------------------
+----------------------------------------------------------+
| All the DFS modules in this series use programs which |
| experiment with the format and contents of discs. These |
| experiments may have disasterous effects if you use any |
| of the programs on discs which store programs or data |
| which you cannot afford to lose. You should first try |
| out the programs using discs that have either been |
| duplicated or, better still, have not been used at all. |
+----------------------------------------------------------+
Writing your own disc formatting program can be quite a useful exercise
because it will give you the opportunity to optimise the speed at which
data can be written to and read from a disc. You might think that all disc
formatting programs are the same but, if you do, then you are quite wrong.
The time taken to write to and read from a disc is affected by the
settings on the keyboard DIL switches and the logical sector offsets
created during formatting. If you have a DIL switch block on your keyboard
you might like to experiment with the settings to increase the performance
of your disc drives.
Figure 1 shows the effect of switching links 3 and 4 on the keyboard DIL
switch block, but do remember that some disc drive manuals specify the
settings to be used and these should not be altered. If you do not have a
switch block fitted on you keyboard the effect of using these switches can
be simulated using Osbyte &FF. Osbyte &FF takes effect after a soft Break
and remains active until a hard Break. All but the slowest disc drives can
be operated with link 3 open (off) and link 4 closed (on) and many modern
disc drives can be used with both links 3 and 4 closed (on). If the
settings for links 3 and 4 have not been specified for your disc drive you
should experiment and use the fastest reliable speed.
+---+---+-----------+-------------+-----------+---------------+---------+
| 3 | 4 | Step time | Settle time | Load time | Osbyte &FF | Speed |
+---+---+-----------+-------------+-----------+---------------+---------+
|on |on | 4 | 16 | 0 | *FX 255,0,207 | Fastest |
|on |off| 6 | 16 | 0 | *FX 255,0,223 | Faster |
|off|on | 6 | 50 | 32 | *FX 255,0,239 | Fast |
|off|off| 24 | 20 | 64 | *FX 255,0,255 | Slow |
+---+---+-----------+-------------+-----------+---------------+---------+
Figure 1. The effect of keyboard switches 3 and 4 on disc access times
----------------------------------------------------------------------
The Acorn DFS uses discs with either 40 or 80 tracks and with 10 sectors
of 256 bytes per track. The physical and logical track numbers must be the
same so that, for example, the ten ID fields on track &01 must all use
logical track number &01. The 10 sectors on each track must use the
logical sector numbers &00 to &09 but the logical and physical sector
numbers do not have to be the same.
Logical sectors &00 and &01 on physical track &00 store the disc
catalogue. The catalogue uses the structure shown in figure 2 and an empty
catalogue must be created by the disc formatting program.
Sector &00 Track &00
--------------------
&00 - &07 First 8 bytes of the 12 byte disc title.
&08 - &0E First file name.
&0F Directory of first file name.
&10 - &16 Second file name.
&17 Directory of second file name.
&18 - &FF and so on for the 31 files.
Sector &01 Track &00
--------------------
&00 - &03 Last 4 bytes of the 12 byte disc title.
&04 Disc cycles (BCD number 0-99).
&05 8 * (Number of catalogue entries).
&06 (bits 0 and 1) Most significant two bits of the number of
sectors on the disc.
(bits 4 and 5) The boot up option set using *OPT4,n.
&07 The least significant 8 bits of the (10 bit) number of sectors
on the disc. The most significant bits are in bits 0 and 1 of
byte &06.
&08 - &09 Load address of first file, least significant 16 bits.
&0A - &0B Execution address of first file, least significant 16 bits.
&0C - &0D Length of first file, least significant 16 bits.
&0E (bits 0 and 1) Startsector of first file, most sig. 2 bits.
(bits 2 and 3) Load address of first file, most sig. 2 bits.
(bits 4 and 5) Length of first file, most sig. 2 bits.
(bits 6 and 7) Execution address of first file, most sig. bits.
&0F Start sector of first file, least significant 8 bits.
&10 - &FF Load address, execution address, file length, and sector number
for every other file on the disc (8 bytes per file). This is
the information given by the *INFO call.
Figure 2. The structure of the DFS catalogue
--------------------------------------------
Although there is a lot of information stored in a disc catalogue nearly
all this information is written by the DFS when the disc is being used. An
Acorn single density formatting program must fill the catalogue with null
bytes (&00) with the exception of bytes &06 and &07 of sector &01. These
bytes must store the number of sectors made available on the disc by the
formatting program.
When a single density formatter is used with an eighty track disc drive it
will create &320 sectors on a disc. Bits 0 and 1 of byte &06 on logical
sector &01 must store the number &03 (%11), and byte &07 of logical sector
&01 must store the number &20. When the program is used with a fourty
track disc drive it will create &190 sectors. Bits 0 and 1 of byte &06 on
logical sector &01 must then store the number &01 (%01), and byte &07 of
logical sector &01 must store the number &90. Figure 3 shows a part of a
sector dump made with a newly formatted eighty track disc. The only
information stored in the empty catalogue is the number of available
sectors on the disc.
Track: 00 Logical Sector: 00
0 1 2 3 4 5 6 7
00 0 0 0 0 0 0 0 0 ........
08 0 0 0 0 0 0 0 0 ........
10 0 0 0 0 0 0 0 0 ........
18 0 0 0 0 0 0 0 0 ........
20 ...
Track: 00 Logical Sector: 01
0 1 2 3 4 5 6 7
00 0 0 0 0 0 0 3 20 .......
08 0 0 0 0 0 0 0 0 ........
10 0 0 0 0 0 0 0 0 ........
18 0 0 0 0 0 0 0 0 ........
20 ...
Figure 3. Part of the catalogue of a newly formatted 80 track disc
------------------------------------------------------------------
The most efficient operation of an Acorn single density disc occurs if
physical sector &00 does not store logical sector &00 on every track. The
optimum distribution of logical sectors with respect to physical sectors
for most disc drives is shown in figure 4. Figure 4 shows that, on track
&00, the physical and logical sector numbers are the same. On track &01,
physical sector &00 stores logical sector &07, physical sector &01 stores
logical sector &08, and so on. This is known as a logical sector offset.
Physical sector numbers
| 00 01 02 03 04 05 06 07 08 09
---+------------------------------
T 00 | 00 01 02 03 04 05 06 07 08 09
r 01 | 07 08 09 00 01 02 03 04 05 06 Logical
a 02 | 04 05 06 07 08 09 00 01 02 03 sector
c 03 | 01 02 03 04 05 06 07 08 09 00 numbers
k 04 | 08 09 00 01 02 03 04 05 06 07
s 05 | 05 06 ...
Figure 4. The logical sectors numbers for optimum speed
-------------------------------------------------------
The logical sector numbers are offset because the disc drive head takes a
predictable amount of time to step from one track to the next when writing
to or reading from a disc.
Consider what will happen if you use the *LOAD command to read a file
which is stored in 10 sectors starting with sector &02 on track &00. This
hypothetical file will be stored on logical sectors &02 to &09 on track
&00, and on logical sectors &00 and &01 on track &01. The sectors on track
&00 will be loaded from sector &02 to sector &09 and then the head will
step in to track &01. This step will take a predictable amount of time
which is long enough for most disc drives to miss logical sector &00 if it
is stored on physical sector &00. The disc would then have to make a
complete revolution before sector &00 reappears. Using the offset
illustrated in figure 4 would ensure that, for most disc drives, sector
&00 on track &01 would become immeadiatly available as the head steps in
from track &00 to &01. All the tracks in figure 4 use the same sector
offset with respect to each other to give an optimum distribution of
logical sectors.
Not all disc drives take the same amount of time to step the head from one
track to another and for this reason the amount of offset used to produce
an optimally formated disc will vary from one disc drive to another. The
distribution of logical sectors shown in figure 4 uses an offset of 3
sectors. That is, sector &00 is offset 3 sectors with respect to sector
&09 on the preceding track. A modern fast disc drive might only require an
offset of 2 sectors so that the physical logical sector &00 on track &01
will be logical sector &08. An old disc drive liberated from the local
junk shop might require an offset of 4 or even 5 sectors.
The program OFFSET can be used to experiment with the amount of offset
given to the logical sector numbers. It can format both 40 and 80 track
discs with any offset from 0 to 9 sectors.
To find the amount of offset needed with a particular disc drive you
should create a set of 10 discs with the offset varying from 0 to 9
sectors. Each disc should be used to measure the time taken to store a
very large file a large number of times within a program loop. It is a
good idea to store the same large file 20 or 30 times and to use a stop
watch rather than the computer to measure the time taken. If you start
with an offset of 9 sectors and work down to zero offset you should find
that the time decreases with each disc until, with one disc, there is an
increase in the time taken to store the files. If, for example, the
increase is with a disc using an offset of 2 sectors then an optimum
offset of 3 sectors is needed for your disc drive. Most disc drives need
an offset of 3 sectors.
10 REM: OFFSET
20 DIM mcode &400
30 oswrch=&FFEE
40 osnewl=&FFE7
50 osword=&FFF1
60 osbyte=&FFF4
70 FORpass=0 TO 2 STEP 2
80 P%=mcode
90 [ OPT pass
100 JSR osnewl
110 .loop
120 LDA &FF \ poll escape flag
130 BPL noescape \ bit 7 set if Escape pressed
140 .escape
150 LDA #&7E
160 JSR osbyte \ acknowledge Escape
170 BRK
180 BRK
190 EQUS "Escape"
200 BRK
210 .noescape
220 LDA track \ load physical track number
230 STA block+7 \ store physical track number
240 BEQ endoffset \ don't offset track zero
250 LDX #36 \ logical track index
260 LDY #38 \ logical sector index
270 .inloop
280 LDA track \ load physical track number
290 STA table,X \ store logical track number
300 LDA shear \ load logical sector offset
310 BEQ zero \ branch if no offset
320 STA temp \ temporary store
330 .offsetloop
340 SEC
350 LDA table,Y \ load logical sector number
360 SBC #1 \ subtract 1
370 BPL positive
380 LDA #9
390 .positive
400 STA table,Y \ store logical sector number - 1
410 DEC temp \ decrement sector offset
420 BNE offsetloop \ offset again
430 .zero
440 DEX
450 DEX
460 TXA
470 TAY \ subtract 4 from Y register
480 DEX
490 DEX \ subtract 4 from X register
500 BPL inloop \ branch if less than 10 sectors
510 .endoffset
520 LDA #&7F
530 LDX #block MOD 256
540 LDY #block DIV 256
550 JSR osword \ format track
560 LDA block+12 \ load result byte
570 BNE error \ format OK if result = 0
580 JSR printtrack \ print track number
590 INC track \ increment track number
600 LDA track \ load track number
610 CMP finish \ is that the last track?
620 BCC loop \ branch if more tracks to format
630 LDA #&7F
640 LDX #catblock MOD 256
650 LDY #catblock DIV 256
660 JSR osword \ store empty catalogue
670 LDA catblock+10 \ check result byte
680 BNE error \ branch if not saved
690 RTS \ return to BASIC
700 .error
710 BRK
720 BRK
730 EQUS "Format error"
740 BRK
750 .printtrack
760 LDA track \ load track number
770 LSR A
780 LSR A
790 LSR A
800 LSR A \ isolate MS nybble
810 JSR nybble \ print MS nybble
820 LDA track \ load track number
830 JSR nybble \ print LS nybble
840 LDA #ASC(" ")
850 JSR oswrch \ print space
860 JMP oswrch \ print space
870 .nybble
880 AND #&0F
890 SED
900 CLC
910 ADC #&90
920 ADC #&40
930 CLD
940 JMP oswrch \ print nybble and return
950 .block
960 EQUB &00 \ drive number 0-3
970 EQUD table \ sector table
980 EQUB &05 \ 5 parameters
990 EQUB &63 \ format track
1000 EQUB &00 \ physical track number 0-79
1010 EQUB &15 \ gap 3
1020 EQUB &2A \ 10 sectors of 256 bytes
1030 EQUB &00 \ gap 5
1040 EQUB &10 \ gap 1
1050 EQUB &00 \ result byte
1060 .table
1070 EQUD &01000000
1080 EQUD &01010000
1090 EQUD &01020000
1100 EQUD &01030000
1110 EQUD &01040000
1120 EQUD &01050000
1130 EQUD &01060000
1140 EQUD &01070000
1150 EQUD &01080000
1160 EQUD &01090000
1170 .catalogue
1180 OPT FNfill(262)
1190 \ store 262 zeros
1200 .sectors
1210 EQUW &2003 \ &320 sectors (80 tracks)
1220 OPT FNfill(248)
1230 \ store 248 zeros
1240 .catblock
1250 EQUB &00 \ drive number 0 - 3
1260 EQUD catalogue \ address of buffer
1270 EQUB &03 \ number of parameters
1280 EQUB &4B \ write data multi-sector
1290 EQUB &00 \ logical track
1300 EQUB &00 \ start logical sector
1310 EQUB &22 \ 2 sectors of 256 bytes
1320 EQUB &00 \ result byte
1330 .track
1340 EQUB &00 \ physical track number
1350 .finish
1360 EQUB &00 \ number of tracks
1370 .shear
1380 EQUB &00 \ sector offset
1390 .temp
1400 EQUB &00 \ sector offset
1410 ]
1420 NEXT
1430 REPEAT
1440 INPUT"Drive number (0-3) "D%
1450 UNTIL D%>-1 AND D%<4
1460 ?block=D%
1470 ?catblock=D%
1480 REPEAT
1490 INPUT"Number of tracks (40/80) "T%
1500 UNTIL T%=40 OR T%=80
1510 ?finish=T%
1520 IF T%=40 THEN ?sectors=&01 : sectors?1=&90
1530 REPEAT
1540 INPUT"Logical sector offset (0-9) "L%
1550 UNTIL L%>-1 AND L%<10
1560 ?shear=L%
1570 INPUT"Ready to format? (Y/N) "yes$
1580 IF LEFT$(yes$,1)="Y" THEN CALL mcode
1590 INPUT'"Another disc? (Y/N) "yes$
1600 IF LEFT$(yes$,1)="Y" THEN RUN
1610 END
1620 DEF FNfill(size)
1630 FOR count = 1 TO size
1640 ?P%=0
1650 P%=P%+1
1660 NEXT
1670 =pass
The logical sector offsets produced by the program OFFSET can be
demonstrated by using the program IDSDUMP introduced in module 0. The
formatted discs it produces can be verified using any DFS verification
program including the program VERIFY, also intorduced in module 0.
00000000 54 68 65 20 41 63 6f 72 6e 20 44 46 53 20 4f 73 |The Acorn DFS Os|
00000010 77 6f 72 64 20 63 6f 6d 6d 61 6e 64 73 20 20 2d |word commands -|
00000020 20 20 62 79 20 20 2d 20 20 47 6f 72 64 6f 6e 20 | by - Gordon |
00000030 48 6f 72 73 69 6e 67 74 6f 6e 0d 2d 2d 2d 2d 2d |Horsington.-----|
00000040 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000070 2d 2d 2d 2d 2d 0d 0d 4d 6f 64 75 6c 65 20 33 2e |-----..Module 3.|
00000080 20 46 6f 72 6d 61 74 74 69 6e 67 20 73 69 6e 67 | Formatting sing|
00000090 6c 65 20 64 65 6e 73 69 74 79 20 64 69 73 63 73 |le density discs|
000000a0 0d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |.---------------|
000000b0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
000000c0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 0d 0d 20 20 20 20 |----------.. |
000000d0 20 20 2b 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d | +-------------|
000000e0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000100 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2b 0d 20 |-------------+. |
00000110 20 20 20 20 20 7c 20 41 6c 6c 20 74 68 65 20 44 | | All the D|
00000120 46 53 20 6d 6f 64 75 6c 65 73 20 69 6e 20 20 74 |FS modules in t|
00000130 68 69 73 20 20 73 65 72 69 65 73 20 20 75 73 65 |his series use|
00000140 20 70 72 6f 67 72 61 6d 73 20 77 68 69 63 68 20 | programs which |
00000150 7c 0d 20 20 20 20 20 20 7c 20 65 78 70 65 72 69 ||. | experi|
00000160 6d 65 6e 74 20 20 77 69 74 68 20 74 68 65 20 66 |ment with the f|
00000170 6f 72 6d 61 74 20 61 6e 64 20 63 6f 6e 74 65 6e |ormat and conten|
00000180 74 73 20 6f 66 20 64 69 73 63 73 2e 20 54 68 65 |ts of discs. The|
00000190 73 65 20 7c 0d 20 20 20 20 20 20 7c 20 65 78 70 |se |. | exp|
000001a0 65 72 69 6d 65 6e 74 73 20 6d 61 79 20 20 68 61 |eriments may ha|
000001b0 76 65 20 64 69 73 61 73 74 65 72 6f 75 73 20 65 |ve disasterous e|
000001c0 66 66 65 63 74 73 20 69 66 20 79 6f 75 20 75 73 |ffects if you us|
000001d0 65 20 61 6e 79 20 7c 0d 20 20 20 20 20 20 7c 20 |e any |. | |
000001e0 6f 66 20 74 68 65 20 70 72 6f 67 72 61 6d 73 20 |of the programs |
000001f0 20 6f 6e 20 20 64 69 73 63 73 20 20 77 68 69 63 | on discs whic|
00000200 68 20 73 74 6f 72 65 20 70 72 6f 67 72 61 6d 73 |h store programs|
00000210 20 6f 72 20 64 61 74 61 20 7c 0d 20 20 20 20 20 | or data |. |
00000220 20 7c 20 77 68 69 63 68 20 79 6f 75 20 63 61 6e | | which you can|
00000230 6e 6f 74 20 61 66 66 6f 72 64 20 74 6f 20 6c 6f |not afford to lo|
00000240 73 65 2e 20 20 59 6f 75 20 20 73 68 6f 75 6c 64 |se. You should|
00000250 20 20 66 69 72 73 74 20 74 72 79 20 7c 0d 20 20 | first try |. |
00000260 20 20 20 20 7c 20 6f 75 74 20 20 74 68 65 20 20 | | out the |
00000270 70 72 6f 67 72 61 6d 73 20 20 75 73 69 6e 67 20 |programs using |
00000280 20 64 69 73 63 73 20 20 74 68 61 74 20 20 68 61 | discs that ha|
00000290 76 65 20 65 69 74 68 65 72 20 62 65 65 6e 20 7c |ve either been ||
000002a0 0d 20 20 20 20 20 20 7c 20 64 75 70 6c 69 63 61 |. | duplica|
000002b0 74 65 64 20 6f 72 2c 20 62 65 74 74 65 72 20 73 |ted or, better s|
000002c0 74 69 6c 6c 2c 20 68 61 76 65 20 6e 6f 74 20 62 |till, have not b|
000002d0 65 65 6e 20 75 73 65 64 20 61 74 20 61 6c 6c 2e |een used at all.|
000002e0 20 20 7c 0d 20 20 20 20 20 20 2b 2d 2d 2d 2d 2d | |. +-----|
000002f0 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d 2d |----------------|
*
00000320 2d 2d 2d 2d 2d 2b 0d 0d 0d 57 72 69 74 69 6e 67 |-----+...Writing|
00000330 20 79 6f 75 72 20 6f 77 6e 20 64 69 73 63 20 66 | your own disc f|
00000340 6f 72 6d 61 74 74 69 6e 67 20 70 72 6f 67 72 61 |ormatting progra|
00000350 6d 20 63 61 6e 20 62 65 20 71 75 69 74 65 20 61 |m can be quite a|
00000360 20 75 73 65 66 75 6c 20 65 78 65 72 63 69 73 65 | useful exercise|
00000370 0d 62 65 63 61 75 73 65 20 69 74 20 77 69 6c 6c |.because it will|
00000380 20 67 69 76 65 20 79 6f 75 20 74 68 65 20 6f 70 | give you the op|
00000390 70 6f 72 74 75 6e 69 74 79 20 74 6f 20 6f 70 74 |portunity to opt|
000003a0 69 6d 69 73 65 20 74 68 65 20 73 70 65 65 64 20 |imise the speed |
000003b0 61 74 20 77 68 69 63 68 0d 64 61 74 61 20 63 61 |at which.data ca|
000003c0 6e 20 62 65 20 77 72 69 74 74 65 6e 20 74 6f 20 |n be written to |
000003d0 61 6e 64 20 72 65 61 64 20 66 72 6f 6d 20 61 20 |and read from a |
000003e0 64 69 73 63 2e 20 59 6f 75 20 6d 69 67 68 74 20 |disc. You might |
000003f0 74 68 69 6e 6b 20 74 68 61 74 20 61 6c 6c 20 64 |think that all d|
00000400 69 73 63 0d 66 6f 72 6d 61 74 74 69 6e 67 20 70 |isc.formatting p|
00000410 72 6f 67 72 61 6d 73 20 61 72 65 20 74 68 65 20 |rograms are the |
00000420 73 61 6d 65 20 62 75 74 2c 20 69 66 20 79 6f 75 |same but, if you|
00000430 20 64 6f 2c 20 74 68 65 6e 20 79 6f 75 20 61 72 | do, then you ar|
00000440 65 20 71 75 69 74 65 20 77 72 6f 6e 67 2e 0d 0d |e quite wrong...|
00000450 54 68 65 20 74 69 6d 65 20 74 61 6b 65 6e 20 74 |The time taken t|
00000460 6f 20 77 72 69 74 65 20 74 6f 20 61 6e 64 20 72 |o write to and r|
00000470 65 61 64 20 66 72 6f 6d 20 61 20 64 69 73 63 20 |ead from a disc |
00000480 69 73 20 61 66 66 65 63 74 65 64 20 62 79 20 74 |is affected by t|
00000490 68 65 0d 73 65 74 74 69 6e 67 73 20 6f 6e 20 74 |he.settings on t|
000004a0 68 65 20 6b 65 79 62 6f 61 72 64 20 44 49 4c 20 |he keyboard DIL |
000004b0 73 77 69 74 63 68 65 73 20 61 6e 64 20 74 68 65 |switches and the|
000004c0 20 6c 6f 67 69 63 61 6c 20 73 65 63 74 6f 72 20 | logical sector |
000004d0 6f 66 66 73 65 74 73 0d 63 72 65 61 74 65 64 20 |offsets.created |
000004e0 64 75 72 69 6e 67 20 66 6f 72 6d 61 74 74 69 6e |during formattin|
000004f0 67 2e 20 49 66 20 79 6f 75 20 68 61 76 65 20 61 |g. If you have a|
00000500 20 44 49 4c 20 73 77 69 74 63 68 20 62 6c 6f 63 | DIL switch bloc|
00000510 6b 20 6f 6e 20 79 6f 75 72 20 6b 65 79 62 6f 61 |k on your keyboa|
00000520 72 64 0d 79 6f 75 20 6d 69 67 68 74 20 6c 69 6b |rd.you might lik|
00000530 65 20 74 6f 20 65 78 70 65 72 69 6d 65 6e 74 20 |e to experiment |
00000540 77 69 74 68 20 74 68 65 20 73 65 74 74 69 6e 67 |with the setting|
00000550 73 20 74 6f 20 69 6e 63 72 65 61 73 65 20 74 68 |s to increase th|
00000560 65 20 70 65 72 66 6f 72 6d 61 6e 63 65 0d 6f 66 |e performance.of|
00000570 20 79 6f 75 72 20 64 69 73 63 20 64 72 69 76 65 | your disc drive|
00000580 73 2e 0d 0d 46 69 67 75 72 65 20 31 20 73 68 6f |s...Figure 1 sho|
00000590 77 73 20 74 68 65 20 65 66 66 65 63 74 20 6f 66 |ws the effect of|
000005a0 20 73 77 69 74 63 68 69 6e 67 20 6c 69 6e 6b 73 | switching links|
000005b0 20 33 20 61 6e 64 20 34 20 6f 6e 20 74 68 65 20 | 3 and 4 on the |
000005c0 6b 65 79 62 6f 61 72 64 20 44 49 4c 0d 73 77 69 |keyboard DIL.swi|
000005d0 74 63 68 20 62 6c 6f 63 6b 2c 20 62 75 74 20 64 |tch block, but d|
000005e0 6f 20 72 65 6d 65 6d 62 65 72 20 74 68 61 74 20 |o remember that |
000005f0 73 6f 6d 65 20 64 69 73 63 20 64 72 69 76 65 20 |some disc drive |
00000600 6d 61 6e 75 61 6c 73 20 73 70 65 63 69 66 79 20 |manuals specify |
00000610 74 68 65 0d 73 65 74 74 69 6e 67 73 20 74 6f 20 |the.settings to |
00000620 62 65 20 75 73 65 64 20 61 6e 64 20 74 68 65 73 |be used and thes|
00000630 65 20 73 68 6f 75 6c 64 20 6e 6f 74 20 62 65 20 |e should not be |
00000640 61 6c 74 65 72 65 64 2e 20 49 66 20 79 6f 75 20 |altered. If you |
00000650 64 6f 20 6e 6f 74 20 68 61 76 65 20 61 0d 73 77 |do not have a.sw|
00000660 69 74 63 68 20 62 6c 6f 63 6b 20 66 69 74 74 65 |itch block fitte|
00000670 64 20 6f 6e 20 79 6f 75 20 6b 65 79 62 6f 61 72 |d on you keyboar|
00000680 64 20 74 68 65 20 65 66 66 65 63 74 20 6f 66 20 |d the effect of |
00000690 75 73 69 6e 67 20 74 68 65 73 65 20 73 77 69 74 |using these swit|
000006a0 63 68 65 73 20 63 61 6e 0d 62 65 20 73 69 6d 75 |ches can.be simu|
000006b0 6c 61 74 65 64 20 75 73 69 6e 67 20 4f 73 62 79 |lated using Osby|
000006c0 74 65 20 26 46 46 2e 20 4f 73 62 79 74 65 20 26 |te &FF. Osbyte &|
000006d0 46 46 20 74 61 6b 65 73 20 65 66 66 65 63 74 20 |FF takes effect |
000006e0 61 66 74 65 72 20 61 20 73 6f 66 74 20 42 72 65 |after a soft Bre|
000006f0 61 6b 0d 61 6e 64 20 72 65 6d 61 69 6e 73 20 61 |ak.and remains a|
00000700 63 74 69 76 65 20 75 6e 74 69 6c 20 61 20 68 61 |ctive until a ha|
00000710 72 64 20 42 72 65 61 6b 2e 20 41 6c 6c 20 62 75 |rd Break. All bu|
00000720 74 20 74 68 65 20 73 6c 6f 77 65 73 74 20 64 69 |t the slowest di|
00000730 73 63 20 64 72 69 76 65 73 20 63 61 6e 0d 62 65 |sc drives can.be|
00000740 20 6f 70 65 72 61 74 65 64 20 77 69 74 68 20 6c | operated with l|
00000750 69 6e 6b 20 33 20 6f 70 65 6e 20 28 6f 66 66 29 |ink 3 open (off)|
00000760 20 61 6e 64 20 6c 69 6e 6b 20 34 20 63 6c 6f 73 | and link 4 clos|
00000770 65 64 20 28 6f 6e 29 20 61 6e 64 20 6d 61 6e 79 |ed (on) and many|
00000780 20 6d 6f 64 65 72 6e 0d 64 69 73 63 20 64 72 69 | modern.disc dri|
00000790 76 65 73 20 63 61 6e 20 62 65 20 75 73 65 64 20 |ves can be used |
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000039c0 20 20 20 20 20 45 51 55 44 20 26 30 31 30 38 30 | EQUD &01080|
000039d0 30 30 30 0d 20 31 31 36 30 20 20 20 20 20 20 20 |000. 1160 |
000039e0 20 20 45 51 55 44 20 26 30 31 30 39 30 30 30 30 | EQUD &01090000|
000039f0 0d 20 31 31 37 30 20 2e 63 61 74 61 6c 6f 67 75 |. 1170 .catalogu|
00003a00 65 0d 20 31 31 38 30 20 20 20 20 20 20 20 20 20 |e. 1180 |
00003a10 4f 50 54 20 46 4e 66 69 6c 6c 28 32 36 32 29 0d |OPT FNfill(262).|
00003a20 20 31 31 39 30 20 20 20 20 20 20 20 20 20 20 20 | 1190 |
00003a30 20 20 20 20 20 20 20 20 20 20 20 20 5c 20 73 74 | \ st|
00003a40 6f 72 65 20 32 36 32 20 7a 65 72 6f 73 0d 20 31 |ore 262 zeros. 1|
00003a50 32 30 30 20 2e 73 65 63 74 6f 72 73 0d 20 31 32 |200 .sectors. 12|
00003a60 31 30 20 20 20 20 20 20 20 20 20 45 51 55 57 20 |10 EQUW |
00003a70 26 32 30 30 33 20 20 20 20 5c 20 26 33 32 30 20 |&2003 \ &320 |
00003a80 73 65 63 74 6f 72 73 20 28 38 30 20 74 72 61 63 |sectors (80 trac|
00003a90 6b 73 29 0d 20 31 32 32 30 20 20 20 20 20 20 20 |ks). 1220 |
00003aa0 20 20 4f 50 54 20 46 4e 66 69 6c 6c 28 32 34 38 | OPT FNfill(248|
00003ab0 29 0d 20 31 32 33 30 20 20 20 20 20 20 20 20 20 |). 1230 |
00003ac0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 5c 20 | \ |
00003ad0 73 74 6f 72 65 20 32 34 38 20 7a 65 72 6f 73 0d |store 248 zeros.|
00003ae0 20 31 32 34 30 20 2e 63 61 74 62 6c 6f 63 6b 0d | 1240 .catblock.|
00003af0 20 31 32 35 30 20 20 20 20 20 20 20 20 20 45 51 | 1250 EQ|
00003b00 55 42 20 26 30 30 20 20 20 20 20 20 5c 20 64 72 |UB &00 \ dr|
00003b10 69 76 65 20 6e 75 6d 62 65 72 20 30 20 2d 20 33 |ive number 0 - 3|
00003b20 0d 20 31 32 36 30 20 20 20 20 20 20 20 20 20 45 |. 1260 E|
00003b30 51 55 44 20 63 61 74 61 6c 6f 67 75 65 20 5c 20 |QUD catalogue \ |
00003b40 61 64 64 72 65 73 73 20 6f 66 20 62 75 66 66 65 |address of buffe|
00003b50 72 0d 20 31 32 37 30 20 20 20 20 20 20 20 20 20 |r. 1270 |
00003b60 45 51 55 42 20 26 30 33 20 20 20 20 20 20 5c 20 |EQUB &03 \ |
00003b70 6e 75 6d 62 65 72 20 6f 66 20 70 61 72 61 6d 65 |number of parame|
00003b80 74 65 72 73 0d 20 31 32 38 30 20 20 20 20 20 20 |ters. 1280 |
00003b90 20 20 20 45 51 55 42 20 26 34 42 20 20 20 20 20 | EQUB &4B |
00003ba0 20 5c 20 77 72 69 74 65 20 64 61 74 61 20 6d 75 | \ write data mu|
00003bb0 6c 74 69 2d 73 65 63 74 6f 72 0d 20 31 32 39 30 |lti-sector. 1290|
00003bc0 20 20 20 20 20 20 20 20 20 45 51 55 42 20 26 30 | EQUB &0|
00003bd0 30 20 20 20 20 20 20 5c 20 6c 6f 67 69 63 61 6c |0 \ logical|
00003be0 20 74 72 61 63 6b 0d 20 31 33 30 30 20 20 20 20 | track. 1300 |
00003bf0 20 20 20 20 20 45 51 55 42 20 26 30 30 20 20 20 | EQUB &00 |
00003c00 20 20 20 5c 20 73 74 61 72 74 20 6c 6f 67 69 63 | \ start logic|
00003c10 61 6c 20 73 65 63 74 6f 72 0d 20 31 33 31 30 20 |al sector. 1310 |
00003c20 20 20 20 20 20 20 20 20 45 51 55 42 20 26 32 32 | EQUB &22|
00003c30 20 20 20 20 20 20 5c 20 32 20 73 65 63 74 6f 72 | \ 2 sector|
00003c40 73 20 6f 66 20 32 35 36 20 62 79 74 65 73 0d 20 |s of 256 bytes. |
00003c50 31 33 32 30 20 20 20 20 20 20 20 20 20 45 51 55 |1320 EQU|
00003c60 42 20 26 30 30 20 20 20 20 20 20 5c 20 72 65 73 |B &00 \ res|
00003c70 75 6c 74 20 62 79 74 65 0d 20 31 33 33 30 20 2e |ult byte. 1330 .|
00003c80 74 72 61 63 6b 0d 20 31 33 34 30 20 20 20 20 20 |track. 1340 |
00003c90 20 20 20 20 45 51 55 42 20 26 30 30 20 20 20 20 | EQUB &00 |
00003ca0 20 20 5c 20 70 68 79 73 69 63 61 6c 20 74 72 61 | \ physical tra|
00003cb0 63 6b 20 6e 75 6d 62 65 72 0d 20 31 33 35 30 20 |ck number. 1350 |
00003cc0 2e 66 69 6e 69 73 68 0d 20 31 33 36 30 20 20 20 |.finish. 1360 |
00003cd0 20 20 20 20 20 20 45 51 55 42 20 26 30 30 20 20 | EQUB &00 |
00003ce0 20 20 20 20 5c 20 6e 75 6d 62 65 72 20 6f 66 20 | \ number of |
00003cf0 74 72 61 63 6b 73 0d 20 31 33 37 30 20 2e 73 68 |tracks. 1370 .sh|
00003d00 65 61 72 0d 20 31 33 38 30 20 20 20 20 20 20 20 |ear. 1380 |
00003d10 20 20 45 51 55 42 20 26 30 30 20 20 20 20 20 20 | EQUB &00 |
00003d20 5c 20 73 65 63 74 6f 72 20 6f 66 66 73 65 74 0d |\ sector offset.|
00003d30 20 31 33 39 30 20 2e 74 65 6d 70 0d 20 31 34 30 | 1390 .temp. 140|
00003d40 30 20 20 20 20 20 20 20 20 20 45 51 55 42 20 26 |0 EQUB &|
00003d50 30 30 20 20 20 20 20 20 5c 20 73 65 63 74 6f 72 |00 \ sector|
00003d60 20 6f 66 66 73 65 74 0d 20 31 34 31 30 20 5d 0d | offset. 1410 ].|
00003d70 20 31 34 32 30 20 4e 45 58 54 0d 20 31 34 33 30 | 1420 NEXT. 1430|
00003d80 20 52 45 50 45 41 54 0d 20 31 34 34 30 20 49 4e | REPEAT. 1440 IN|
00003d90 50 55 54 22 44 72 69 76 65 20 6e 75 6d 62 65 72 |PUT"Drive number|
00003da0 20 28 30 2d 33 29 20 22 44 25 0d 20 31 34 35 30 | (0-3) "D%. 1450|
00003db0 20 55 4e 54 49 4c 20 44 25 3e 2d 31 20 41 4e 44 | UNTIL D%>-1 AND|
00003dc0 20 44 25 3c 34 0d 20 31 34 36 30 20 3f 62 6c 6f | D%<4. 1460 ?blo|
00003dd0 63 6b 3d 44 25 0d 20 31 34 37 30 20 3f 63 61 74 |ck=D%. 1470 ?cat|
00003de0 62 6c 6f 63 6b 3d 44 25 0d 20 31 34 38 30 20 52 |block=D%. 1480 R|
00003df0 45 50 45 41 54 0d 20 31 34 39 30 20 49 4e 50 55 |EPEAT. 1490 INPU|
00003e00 54 22 4e 75 6d 62 65 72 20 6f 66 20 74 72 61 63 |T"Number of trac|
00003e10 6b 73 20 28 34 30 2f 38 30 29 20 22 54 25 0d 20 |ks (40/80) "T%. |
00003e20 31 35 30 30 20 55 4e 54 49 4c 20 54 25 3d 34 30 |1500 UNTIL T%=40|
00003e30 20 4f 52 20 54 25 3d 38 30 0d 20 31 35 31 30 20 | OR T%=80. 1510 |
00003e40 3f 66 69 6e 69 73 68 3d 54 25 0d 20 31 35 32 30 |?finish=T%. 1520|
00003e50 20 49 46 20 54 25 3d 34 30 20 54 48 45 4e 20 3f | IF T%=40 THEN ?|
00003e60 73 65 63 74 6f 72 73 3d 26 30 31 20 3a 20 73 65 |sectors=&01 : se|
00003e70 63 74 6f 72 73 3f 31 3d 26 39 30 0d 20 31 35 33 |ctors?1=&90. 153|
00003e80 30 20 52 45 50 45 41 54 0d 20 31 35 34 30 20 49 |0 REPEAT. 1540 I|
00003e90 4e 50 55 54 22 4c 6f 67 69 63 61 6c 20 73 65 63 |NPUT"Logical sec|
00003ea0 74 6f 72 20 6f 66 66 73 65 74 20 28 30 2d 39 29 |tor offset (0-9)|
00003eb0 20 22 4c 25 0d 20 31 35 35 30 20 55 4e 54 49 4c | "L%. 1550 UNTIL|
00003ec0 20 4c 25 3e 2d 31 20 41 4e 44 20 4c 25 3c 31 30 | L%>-1 AND L%<10|
00003ed0 0d 20 31 35 36 30 20 3f 73 68 65 61 72 3d 4c 25 |. 1560 ?shear=L%|
00003ee0 0d 20 31 35 37 30 20 49 4e 50 55 54 22 52 65 61 |. 1570 INPUT"Rea|
00003ef0 64 79 20 74 6f 20 66 6f 72 6d 61 74 3f 20 28 59 |dy to format? (Y|
00003f00 2f 4e 29 20 22 79 65 73 24 0d 20 31 35 38 30 20 |/N) "yes$. 1580 |
00003f10 49 46 20 4c 45 46 54 24 28 79 65 73 24 2c 31 29 |IF LEFT$(yes$,1)|
00003f20 3d 22 59 22 20 54 48 45 4e 20 43 41 4c 4c 20 6d |="Y" THEN CALL m|
00003f30 63 6f 64 65 0d 20 31 35 39 30 20 49 4e 50 55 54 |code. 1590 INPUT|
00003f40 27 22 41 6e 6f 74 68 65 72 20 64 69 73 63 3f 20 |'"Another disc? |
00003f50 28 59 2f 4e 29 20 22 79 65 73 24 0d 20 31 36 30 |(Y/N) "yes$. 160|
00003f60 30 20 49 46 20 4c 45 46 54 24 28 79 65 73 24 2c |0 IF LEFT$(yes$,|
00003f70 31 29 3d 22 59 22 20 54 48 45 4e 20 52 55 4e 0d |1)="Y" THEN RUN.|
00003f80 20 31 36 31 30 20 45 4e 44 0d 20 31 36 32 30 20 | 1610 END. 1620 |
00003f90 44 45 46 20 46 4e 66 69 6c 6c 28 73 69 7a 65 29 |DEF FNfill(size)|
00003fa0 0d 20 31 36 33 30 20 46 4f 52 20 63 6f 75 6e 74 |. 1630 FOR count|
00003fb0 20 3d 20 31 20 54 4f 20 73 69 7a 65 0d 20 31 36 | = 1 TO size. 16|
00003fc0 34 30 20 3f 50 25 3d 30 0d 20 31 36 35 30 20 50 |40 ?P%=0. 1650 P|
00003fd0 25 3d 50 25 2b 31 0d 20 31 36 36 30 20 4e 45 58 |%=P%+1. 1660 NEX|
00003fe0 54 0d 20 31 36 37 30 20 3d 70 61 73 73 0d 0d 0d |T. 1670 =pass...|
00003ff0 54 68 65 20 6c 6f 67 69 63 61 6c 20 73 65 63 74 |The logical sect|
00004000 6f 72 20 6f 66 66 73 65 74 73 20 70 72 6f 64 75 |or offsets produ|
00004010 63 65 64 20 62 79 20 74 68 65 20 70 72 6f 67 72 |ced by the progr|
00004020 61 6d 20 4f 46 46 53 45 54 20 63 61 6e 20 62 65 |am OFFSET can be|
00004030 20 0d 64 65 6d 6f 6e 73 74 72 61 74 65 64 20 62 | .demonstrated b|
00004040 79 20 75 73 69 6e 67 20 74 68 65 20 70 72 6f 67 |y using the prog|
00004050 72 61 6d 20 49 44 53 44 55 4d 50 20 69 6e 74 72 |ram IDSDUMP intr|
00004060 6f 64 75 63 65 64 20 69 6e 20 6d 6f 64 75 6c 65 |oduced in module|
00004070 20 30 2e 20 54 68 65 0d 66 6f 72 6d 61 74 74 65 | 0. The.formatte|
00004080 64 20 64 69 73 63 73 20 69 74 20 70 72 6f 64 75 |d discs it produ|
00004090 63 65 73 20 63 61 6e 20 62 65 20 76 65 72 69 66 |ces can be verif|
000040a0 69 65 64 20 75 73 69 6e 67 20 61 6e 79 20 44 46 |ied using any DF|
000040b0 53 20 76 65 72 69 66 69 63 61 74 69 6f 6e 0d 70 |S verification.p|
000040c0 72 6f 67 72 61 6d 20 69 6e 63 6c 75 64 69 6e 67 |rogram including|
000040d0 20 74 68 65 20 70 72 6f 67 72 61 6d 20 56 45 52 | the program VER|
000040e0 49 46 59 2c 20 61 6c 73 6f 20 69 6e 74 6f 72 64 |IFY, also intord|
000040f0 75 63 65 64 20 69 6e 20 6d 6f 64 75 6c 65 20 30 |uced in module 0|
00004100 2e 0d |..|
00004102 
26-08-88/T\DFS03.m0
26-08-88/T\DFS03.m1
26-08-88/T\DFS03.m2
26-08-88/T\DFS03.m4
26-08-88/T\DFS03.m5
.