Getafix
Experienced Member
I knew almost nothing about this, and this is what I learnt, documented here should I or someone else need it again later:
1) My BIOS (01/10/84 U27=6181028, U47=6181029) would not work. Could not boot from SCSI. Replaced with AMI BIOS.
a) EZ-SCSI did not see my Adaptec card till I replaced the BIOS
b) I am using MS-DOS 6.22
2) SCSI drives show up after the PC BIOS configured hard drives
3) On my Adaptec AHA-1520 (using its BIOS, other adapters may vary - maybe map 4 DOS drives or something):
a) I left all but 2 jumpers at factory settings (see below) but only 1 change did anything
b) Only SCSI ID 0 & 1 are mapped to DOS (so use fdisk to partition), with no PC BIOS HD present
b.1) PC BIOS drives show up first and at most 2 SCSI disks in the slots left over out of max 2 DOS slots
b.2) Any SCSI drives not mapped to the 2 possible DOS slots can be used through ASPIDISK.SYS
c) The J5 R- jumper to "Enable/disable greater than 1 GB translation" didn't do anything for me
c.1) These "DOS mapped drives", if using BlueSCSI (and I presume SCSI2SD) weren't usable bigger than 1024M
c.2) Use a file size of 1025M for SCSI IDs 1 & 2 (Unless > 1GB translation works for you, I guess, on DOS mapped drives)
c.2.1) a 1025M file is 1024M in fdisk and formats to 1023.98M. 1024M file size does a little less
d) SCSI ID 2+ disks (or any non-SCSI BIOS to DOS mapped drives)
d.1) The max usable file size for non-DOS mapped (usually SCSI ID 2+) is 8040M.
d.1.1) Anything bigger and AFDISK sees > 1024 Cylinders and will just ignore that "area" of disk
d.2) you need ASPIDISK.SYS (which needs ASPI2DOS.SYS or whatever variant for your card) to see them
d.2.1) add /D (ex. DEVICE=ASPI2DOS.SYS /D) to the call on both for useful info
d.3) To partition use AFDISK from EZ-SCSI
d.3.1) for 8040M files I used end cylinders of 260,521,782,1023 for 3x 2047M and 1x 1890M partitions
e) Jumper J5 M1 (Enable Fast SCSI) turned off a lot of SCSI BIOS prints and waits and made the boot go way faster
h) PC-TOOLS' SI reports a disk rating of 31 to 32 (normal is 5.2 for AT @ 6MHz) and transfer speed of ~933 Kb/Sec
h.1) I used SCSI ID 0 & 2 skipping 1 (and no BIOS HD).
h.2) If I add an ID 1 disk, SI reports 29.1 and ~873 Kb/Sec on both drives. Who knows why it changes?
I used the Unix utility truncate (also in wsl or installed with Git under windows) to make empty files on the SD card to use with BlueSCSI. Syntax is:
truncate -s <size> <file> where size is something like 1025M or 8040M or 8G or whatever. File is HDx.hda where x is the SCSI ID (example HD0.HDA)
So, steps would be:
Jump > 1 GB jumper (and maybe it does something)
Make files on SD
Install SCSI & BlueSCSI
Boot and install DOS
Install EZ-SCSI
use AFDISK
Jump "Fast SCSI" jumper (or do it earlier but it helped me to see the bios do things)
and you can have a lot of pretty fast disk space!
Thank you
Stefan
1) My BIOS (01/10/84 U27=6181028, U47=6181029) would not work. Could not boot from SCSI. Replaced with AMI BIOS.
a) EZ-SCSI did not see my Adaptec card till I replaced the BIOS
b) I am using MS-DOS 6.22
2) SCSI drives show up after the PC BIOS configured hard drives
3) On my Adaptec AHA-1520 (using its BIOS, other adapters may vary - maybe map 4 DOS drives or something):
a) I left all but 2 jumpers at factory settings (see below) but only 1 change did anything
b) Only SCSI ID 0 & 1 are mapped to DOS (so use fdisk to partition), with no PC BIOS HD present
b.1) PC BIOS drives show up first and at most 2 SCSI disks in the slots left over out of max 2 DOS slots
b.2) Any SCSI drives not mapped to the 2 possible DOS slots can be used through ASPIDISK.SYS
c) The J5 R- jumper to "Enable/disable greater than 1 GB translation" didn't do anything for me
c.1) These "DOS mapped drives", if using BlueSCSI (and I presume SCSI2SD) weren't usable bigger than 1024M
c.2) Use a file size of 1025M for SCSI IDs 1 & 2 (Unless > 1GB translation works for you, I guess, on DOS mapped drives)
c.2.1) a 1025M file is 1024M in fdisk and formats to 1023.98M. 1024M file size does a little less
d) SCSI ID 2+ disks (or any non-SCSI BIOS to DOS mapped drives)
d.1) The max usable file size for non-DOS mapped (usually SCSI ID 2+) is 8040M.
d.1.1) Anything bigger and AFDISK sees > 1024 Cylinders and will just ignore that "area" of disk
d.2) you need ASPIDISK.SYS (which needs ASPI2DOS.SYS or whatever variant for your card) to see them
d.2.1) add /D (ex. DEVICE=ASPI2DOS.SYS /D) to the call on both for useful info
d.3) To partition use AFDISK from EZ-SCSI
d.3.1) for 8040M files I used end cylinders of 260,521,782,1023 for 3x 2047M and 1x 1890M partitions
e) Jumper J5 M1 (Enable Fast SCSI) turned off a lot of SCSI BIOS prints and waits and made the boot go way faster
h) PC-TOOLS' SI reports a disk rating of 31 to 32 (normal is 5.2 for AT @ 6MHz) and transfer speed of ~933 Kb/Sec
h.1) I used SCSI ID 0 & 2 skipping 1 (and no BIOS HD).
h.2) If I add an ID 1 disk, SI reports 29.1 and ~873 Kb/Sec on both drives. Who knows why it changes?
I used the Unix utility truncate (also in wsl or installed with Git under windows) to make empty files on the SD card to use with BlueSCSI. Syntax is:
truncate -s <size> <file> where size is something like 1025M or 8040M or 8G or whatever. File is HDx.hda where x is the SCSI ID (example HD0.HDA)
So, steps would be:
Jump > 1 GB jumper (and maybe it does something)
Make files on SD
Install SCSI & BlueSCSI
Boot and install DOS
Install EZ-SCSI
use AFDISK
Jump "Fast SCSI" jumper (or do it earlier but it helped me to see the bios do things)
and you can have a lot of pretty fast disk space!
Thank you
Stefan
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