Posted By
Litwr
on 2007-11-13
02:55:19
|  Errors in 1551/1541 User Manuals?
1) I can't use full form of DOS commands BUFFER-POINTER, BLOCK-ALLOCATE, ...
with Yape true 1551 emulation and plus4emu. Is it error in the manual?
2) The 1551 manual describes '%' command to change drive number. It can't work
with Yape and plus4emu. I wrote
OPEN15,8,15
PRINT#15,"%"
DLOAD"MYFILE",U9
but got error message. BTW the mentioned manual also describes "%R" command
to change unit number which also sets number of retries during disk read...
Is it possible to change drive number? What purpose of C1551 DOS "%R"
command?
Do these commands work at real iron?
And another DOS oddness. There is a BASIC commands sequence
DLOAD"PROGRAM",U9
OPEN8,8,8,"MISSSEDFILE,S,R"
?DS$
00, OK, 00, 00
The MISSEDFILE is absent at the disk so DS$ shows Unit 9 state. IMHO
'U#' addition to BASIC 3.5 DOS commands changes default device for DS$.
Is there a simple way to set default device for DS$?
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Posted By
JamesC
on 2007-11-13
07:50:28
| Re: Errors in 1551/1541 User Manuals?
a) You haven't closed the channel to the 1551:
OPEN 15,8,15
PRINT#15,"%" : REM Toggles between 8 and 9 - use PRINT#15,"%8" or PRINT#15,"%9" to force a specific drive number
CLOSE 15
DLOAD"MYFILE",U9
b) DS$ reports the status of the disk drive last accessed. There is no 'default drive' for DS$ -- it is up to the programmer to check the disk status after each disk access. 
c) %R sets the number of retries to read a 'bad' sector:
OPEN 15,8,15 : PRINT#15,"%R"+CHR$(1) : CLOSE 15 would set the drive to only try twice -- the original attempt plus one retry. Allowable values are 1 to 255 (if you're desperate to recover a damaged disk, maybe 255 retries is acceptable?!).
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Posted By
JamesC
on 2007-11-13
07:57:02
| Re: Errors in 1551/1541 User Manuals?
d) For direct access DOS commands, be sure that you are using "drive 0" in the command, not the "unit number" of 8 or 9. Yes, these command should work. Only "M-R" and "M-W" cannot be spelled out in full.
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Posted By
Litwr
on 2007-11-14
02:49:17
| Re: Errors in 1551/1541 User Manuals?
Thank you very much for this information! 
However try to test the DS$ example - it shows some kind of fixation for drive number for DS$....
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Posted By
SVS
on 2007-11-14
08:17:56
 | Re: Errors in 1551/1541 User Manuals?
I'm quite sure that:
a) DLOAD and DS$ always get from device #8; then DLOAD "FILE",u9 cannot work
b) Command % does not work without parameter (manual has a mistake)
c) Command %R *should* set the sector interleave value (8 for 1551, 10 for 1541)
Waitin' for confirmations...
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Posted By
JamesC
on 2007-11-14
20:55:27
| Re: Errors in 1551/1541 User Manuals?
SVS --
a) works for me under YAPE 0.70 as expected. DLOAD"filename",U9 works, and I get a proper DS$.
However I am testing in direct mode, not in program mode. I do not remember a DLOAD from Units other than 8 being a bug.
Maybe you are thinking of dL"* (Shift-Run/Stop) always loading from device 8?
b) I did not test. My manual is the all-grey US/UK 1551 manual.
c) %R is retry -- %S is sector interleave value, per my manual.
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Posted By
Litwr
on 2007-11-16
04:06:11
| Re: Errors in 1551/1541 User Manuals?
plz look at my example again
DLOAD"PROGRAM",U9
rem PROGRAM is at diskdrive 9 and successfully loaded - THIS SETS DS$!!!
OPEN8,8,8,"MISSSEDFILE,S,R"
rem MISSEDFILE is absent at diskdrive 8 and can't be loaded
?DS$
rem ds$ shows results for the FIRST operation!!!
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Posted By
siz
on 2007-11-16
11:29:57
| Re: Errors in 1551/1541 User Manuals?
I think that DS$ is only refreshed after executing dedicated disk commands. Operations on OPENed file channels don't touch DS$.
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Posted By
Litwr
on 2007-11-20
00:56:25
| Re: Errors in 1551/1541 User Manuals?
LOAD command doesn't set DS$ for proper diskdrive too.
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Posted By
siz
on 2007-11-20
09:13:14
| Re: Errors in 1551/1541 User Manuals?
Yeah, I meant DLOAD, DSAVE, DIRECTORY, SCRATCH, HEADER (and I don't remember if there were more) commands on dedicated disk commands.
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Posted By
Litwr
on 2007-11-21
06:53:27
| Re: Errors in 1551/1541 User Manuals?
I think there must be some POKE address which can allow to change DS$ fixation.
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