voidstar78
Veteran Member
In the 80s, I was lucky to have a Tandy 1000SX - which I used daily for about 5 years (mastered that config.sys and self taught some Turbo Pascal v3 to v7). I've since forgotten nearly all of that, but some of it is slowly coming back to me.
Recently, I was lucky to come across a pristine condition IBM PC 5150. It is a "B model" with 256KB RAM, both disk drives are 5.25" DD 360KB, and it has the 63W power supply, stock 8088, and that cassette port (which I verified works, can save and load my BASIC programs). Also came with an interesting CGA card. More on the CGA in another thread....
I didn't want to put any wear and tear on the 5.25" disk drives, so I ordered one of the HXC floppy emulators. It was a tad confusing at first, but after some trial and error I've gotten it working very well: I can handle both 360KB and 720KB images, switching between A: and B: drives, and can swap HFE files without having to muck with any dip switches or reboot. My only issue is that I can only handle DD 360/720KB, I can't handle any HD 1.22/1.44MB images. And I think it is my disk controller that is the limiting factor (which I think I did verify in some IBM documentation that HD media wasn't supported in the original IBM PC disk controllers).
So, eventually I ordered an XT-IDE with 128MB CF card. It worked "out of the box" as soon as it arrived, booting to DOS 6.22 and preloaded with a bunch of things. But then I broke it.... The story here is: I tried to make my own backup image of the CF card. I used the only CF card reader that I had - and long story short, I think that card reader corrupted the disk. I was never able to actually image that CF card (my Win10 machine just kept bouncing a drive letter on and off, which was a bad sign). And when I tried to boot my XT-IDE with that CF again, it just said "Boot sector not found." Now I'm sure there are a lot of ways to fix that -- but I just ordered another XT-IDE and CF card.
Meanwhile, I've challenged myself to re-initialize that CF card myself. I don't have another PC with any physical disk drives (or disk media). Here is a summary of some interesting things I re-discovered about DOS:
- Early DOS is limited to 32MB partitions, specifically before 3.31
- Later DOS requires over 256KB RAM (just to run the installer! I'm not kidding, even PC-DOS 4.0 just said "Out of memory" when the installer ran)
- I tried creating a 720KB version of a MS-DOS 6.22 install, but it never would boot (when I create the PC-DOS 3.30 image, I end up with RSA-H attributes on the files ibmbio.com, ibmdos.com and dos00i.400 - thankfully, somehow the zip and HXC image creation is preserving those attributes and it all just boots -- but I thought SYS.COM did a little boot more to prepare a disk for actually being bootable, some 512byte MBR?)
- I tried booting to DOS 3.X, then running the DOS 6.X copy of SYS.COM to initialize a blank disk image - but it just says "incorrect DOS version" and won't run
So.... Then I remembered I used DR-DOS for a long time back in the day.
- I tried DR DOS 5.0 since it still came on 3.5" 720KB disk images, but it said quite explicitly: "Sorry, this program requires 512 Kbytes of free memory".
- Then I tried DR DOS 3.41 ! That was a winner... Sort of.
I used it's FDISK to initialize a full 128MB primary active partition on the CF card. I think the FORMAT.COM was on disk2, so had to image+mount that (put it in B: drive), and format the partition. Then I ran the DR DOS 3.41 setup. That worked, up until the SYS.COM part: "SYS.COM did not run successfully."
I'm not sure why the setup reported this error. I exited back to the command prompt, and just ran SYS.COM myself: SYS C: which then reported the following:
"Writing new boot sector.
"System files copied."
So that ran manually just fine, and I ended up with DRBIOS.sys and DRBDOS.SYS COMMAND.COM on C: - and then my XT-IDE would again boot to C: just fine also. (there was a DRDOS folder, but it empty - so I just copied A: and B: contents to there, both disks of DRDOS).
DRDOS comes with EDITOR.EXE - use CTRL-K CTRL-X to save and exit from that (like for creating autoexec.bat and config.sys)
So that was the adventure - my XT-IDE worked out of the box and I had a 128MB partition on my 5150 Type B with 256KB... but I corrupted my CF card somehow. So I manually got it booting again. I couldn't get an MS-DOS 6.22 image for my 720KB limited disk controller - the PC/DR/MS DOS installers from ver 4 and 5 required over 256KB (no idea why, for an installer...), and older 3.30 or older DOS only let me create 32MB partitions.... DR-DOS 3.41 was my best compromise in the situation: if your XT-IDE CF becomes corrupted or lost and you have a 256KB 5150, you can get back to a single 128MB partition using DRDOS 3.41
And this partition should remain compatible if I ever do get a 720KB DOS 6.22 image in the future (I'll try creating one when I get my 2nd XT-IDE and CF card next week). Or maybe I'll find a newer controller card.
Now I'll start loading it up with content, so I don't have to flip between 720KB disk images on the HXC so much
-v
Recently, I was lucky to come across a pristine condition IBM PC 5150. It is a "B model" with 256KB RAM, both disk drives are 5.25" DD 360KB, and it has the 63W power supply, stock 8088, and that cassette port (which I verified works, can save and load my BASIC programs). Also came with an interesting CGA card. More on the CGA in another thread....
I didn't want to put any wear and tear on the 5.25" disk drives, so I ordered one of the HXC floppy emulators. It was a tad confusing at first, but after some trial and error I've gotten it working very well: I can handle both 360KB and 720KB images, switching between A: and B: drives, and can swap HFE files without having to muck with any dip switches or reboot. My only issue is that I can only handle DD 360/720KB, I can't handle any HD 1.22/1.44MB images. And I think it is my disk controller that is the limiting factor (which I think I did verify in some IBM documentation that HD media wasn't supported in the original IBM PC disk controllers).
So, eventually I ordered an XT-IDE with 128MB CF card. It worked "out of the box" as soon as it arrived, booting to DOS 6.22 and preloaded with a bunch of things. But then I broke it.... The story here is: I tried to make my own backup image of the CF card. I used the only CF card reader that I had - and long story short, I think that card reader corrupted the disk. I was never able to actually image that CF card (my Win10 machine just kept bouncing a drive letter on and off, which was a bad sign). And when I tried to boot my XT-IDE with that CF again, it just said "Boot sector not found." Now I'm sure there are a lot of ways to fix that -- but I just ordered another XT-IDE and CF card.
Meanwhile, I've challenged myself to re-initialize that CF card myself. I don't have another PC with any physical disk drives (or disk media). Here is a summary of some interesting things I re-discovered about DOS:
- Early DOS is limited to 32MB partitions, specifically before 3.31
- Later DOS requires over 256KB RAM (just to run the installer! I'm not kidding, even PC-DOS 4.0 just said "Out of memory" when the installer ran)
- I tried creating a 720KB version of a MS-DOS 6.22 install, but it never would boot (when I create the PC-DOS 3.30 image, I end up with RSA-H attributes on the files ibmbio.com, ibmdos.com and dos00i.400 - thankfully, somehow the zip and HXC image creation is preserving those attributes and it all just boots -- but I thought SYS.COM did a little boot more to prepare a disk for actually being bootable, some 512byte MBR?)
- I tried booting to DOS 3.X, then running the DOS 6.X copy of SYS.COM to initialize a blank disk image - but it just says "incorrect DOS version" and won't run
So.... Then I remembered I used DR-DOS for a long time back in the day.
- I tried DR DOS 5.0 since it still came on 3.5" 720KB disk images, but it said quite explicitly: "Sorry, this program requires 512 Kbytes of free memory".
- Then I tried DR DOS 3.41 ! That was a winner... Sort of.
I used it's FDISK to initialize a full 128MB primary active partition on the CF card. I think the FORMAT.COM was on disk2, so had to image+mount that (put it in B: drive), and format the partition. Then I ran the DR DOS 3.41 setup. That worked, up until the SYS.COM part: "SYS.COM did not run successfully."
I'm not sure why the setup reported this error. I exited back to the command prompt, and just ran SYS.COM myself: SYS C: which then reported the following:
"Writing new boot sector.
"System files copied."
So that ran manually just fine, and I ended up with DRBIOS.sys and DRBDOS.SYS COMMAND.COM on C: - and then my XT-IDE would again boot to C: just fine also. (there was a DRDOS folder, but it empty - so I just copied A: and B: contents to there, both disks of DRDOS).
DRDOS comes with EDITOR.EXE - use CTRL-K CTRL-X to save and exit from that (like for creating autoexec.bat and config.sys)
So that was the adventure - my XT-IDE worked out of the box and I had a 128MB partition on my 5150 Type B with 256KB... but I corrupted my CF card somehow. So I manually got it booting again. I couldn't get an MS-DOS 6.22 image for my 720KB limited disk controller - the PC/DR/MS DOS installers from ver 4 and 5 required over 256KB (no idea why, for an installer...), and older 3.30 or older DOS only let me create 32MB partitions.... DR-DOS 3.41 was my best compromise in the situation: if your XT-IDE CF becomes corrupted or lost and you have a 256KB 5150, you can get back to a single 128MB partition using DRDOS 3.41
And this partition should remain compatible if I ever do get a 720KB DOS 6.22 image in the future (I'll try creating one when I get my 2nd XT-IDE and CF card next week). Or maybe I'll find a newer controller card.
Now I'll start loading it up with content, so I don't have to flip between 720KB disk images on the HXC so much
-v