charles@c3pe.UUCP (Charles Green) (06/04/89)
Now that I have an Atari drive that can read and write 256-byte sectors, I'd
like to try accessing floppies from a CP/M machine in our office, which can
write 40-track, single-sided, double density 256-byte sectors. However, I
haven't been able to successfully use SIO to read the sectors.
I have a BASIC program with machine language assist which can read/write the
standard 128-byte sectors via SIO calls, stuffing 'R' into DCOMND and filling
in the other fields of the DCB for sector number and buffer. I hoped that by
putting 256 into DBYTLO/HI I would be able to read the sectors, but I only got
data for the first three sectors, which leads me to believe I'm still only
giving the "single-density" read command, and the drive is being tolerant in
case I'm trying to boot from PROM.
So, can anyone shed some light on this issue? Thanks for any information...
--
{decuac.dec.com,cucstud,sundc}!c3pe!charles ex::!echo Boo:chasm@killer.DALLAS.TX.US (Charles Marslett) (06/05/89)
In article <7097@c3pe.UUCP>, charles@c3pe.UUCP (Charles Green) writes: > Now that I have an Atari drive that can read and write 256-byte sectors, I'd > like to try accessing floppies from a CP/M machine in our office, which can > write 40-track, single-sided, double density 256-byte sectors. However, I > haven't been able to successfully use SIO to read the sectors. > So, can anyone shed some light on this issue? Thanks for any information... > -- > {decuac.dec.com,cucstud,sundc}!c3pe!charles ex::!echo Boo: You should be able to do that (I once wrote an ATR8000 "driver" that allowed it to read/write 128-byte 1050-double-density disks, and another than read 1024-byte CP/M disks). The major gotchas are (1) use $E459, not $E453 (the disk handler), since $E453 code resets the length to 128 bytes before doing anything, and (2) make sure you set the drive to double-density mode (if you need to) -- this depends on the type and generation of the drive . . . they're all different Charles Marslett chasm@killer.dallas.tx.us
rcbamw@eutrc3.UUCP (m.waucomont) (06/06/89)
In article <7097@c3pe.UUCP> charles@c3pe.UUCP (Charles Green) writes: >Now that I have an Atari drive that can read and write 256-byte sectors, I'd >like to try accessing floppies from a CP/M machine in our office, which can >write 40-track, single-sided, double density 256-byte sectors. However, I >haven't been able to successfully use SIO to read the sectors. >So, can anyone shed some light on this issue? Thanks for any information... Yep, the sources to read/write 256 bytes from/to a modified drive are on its way to you, Charles. Anybody else interested in these sources can drop a line (I don't want to blow that much info over comp.sys.atari.8bit). I will mail them then :-) Michel 'Mikki' Waucomont
slackey@bbn.com (Stan Lackey) (06/06/89)
In article <7097@c3pe.UUCP> charles@c3pe.UUCP (Charles Green) writes: >Now that I have an Atari drive that can read and write 256-byte sectors, I'd >like to try accessing floppies from a CP/M machine in our office, which can >write 40-track, single-sided, double density 256-byte sectors. However, I >haven't been able to successfully use SIO to read the sectors. > >I have a BASIC program with machine language assist which can read/write the >standard 128-byte sectors via SIO calls, stuffing 'R' into DCOMND and filling >in the other fields of the DCB for sector number and buffer. I hoped that by >putting 256 into DBYTLO/HI I would be able to read the sectors, but I only got >data for the first three sectors, which leads me to believe I'm still only >giving the "single-density" read command... It sounds like you have the XF551. I have hacked around doing exactly what you are doing. I believe that the way the density is selected is by using 'R' with the number of bytes; 128 selects single density (which is what the first three sectors are written in) and 256 selects double density. That's all. Note: the standard SIO entry (the address escapes me) resets the byte count to 128! If you have the OS listing, you should be able to figure out the proper address; that is, the routine that is called after SIO sets byte count to 128. I can look it up if you need it. My mission was to transfer files from IBM PC to Atari. A kind soul on the net came to my aid with a program to r/w Mydos 256-sector files with a PC, and as it turns out Spartados can r/w Mydos disks. I was prepared to write all that stuff myself! It all works beautiful now. -Stan