I would like to install MS-DOS 5 on an Amstrad PC-20. It only has a single 3 1/2" drive, no HDD (although I am about to do an XT-IDE with CF card for that).
Here’s what I have:
The 3 disk images that comprise the DOS installation
My modern PC (where the images are), which lacks a 3 1/2" drive (of course)
The target PC wit its single 3 1/2" drive
An old non windows based logic analyzer that has a 3 1/2" drive, can read FAT16, and via LAN can transfer files to and from the modern PC.
In the short term, I want a floppy based DOS 5 installation. Basically, I want to create the 3 floppies from the 3 images. My understanding is that creating a bootable partition on the future CF card is easier with DOS 5 (I currently only have a DOS 3.3 disk for the Amstrad).
In the long term (for when I get my XT-ide and CF adapter), I would like to have a bootable DOS 5 partition on the CF card. I do have a CF reader for thew modern PC. If the floppy installation works, I figure I can format the CF on the Amstrad and install that way.
It’s way easier to get a working set of bootable 3.5" floppies from someone else, than to jump through all the hoops needed to make them yourself.
Alternative is a USB-to-Floppy drive and image the disks via using your main PC. Again, eBay is best option.
Really, Really, hard way:
Use a hex viewer to view the first DOS image.
IF you have any version of DEBUG on the Amstrad use that to enter each HEX value of each byte of the disk image
Using DEBUG write that to the blank floppy. Its only about 40,000 bytes for the bookblock and command.com plus io.sys and msdos.sys.
No-one in the right mind would do this. But it is technically do-able.
FYI, DOS floppies are FAT12, not FAT16.
If the logic analyser can only transfer files, you are a bit stuck to be honest, as you need a working bootblock which isn’t a file that’s listed in the directory of a disk.
I would (first) use FreeDOS.
It’s possible to do that without disks. Or ask someone else to do or buy or borrow an USB FDD.
Note that there are limitations of partition size. (Depending on DOS version and BIOS). 2GB or less (or was it 500 MB) , especially when using DOS 3. But you can create more partitions.
I read about issues with some brands (or sizes) of cards. Then try another. Easier would be a HDD of course. It also might be difficult to change disks.
One disk is a boot disk. You need to make partitions with fdisk and then format it. Maybe you have to change BIOS settings (LBA or IDE large drive support).
I’ve never installed DOS on a card, but it should work. There are several sites on the web.
I think I would get a USB floppy disk drive and write the images raw to the floppies using whatever tool is appropriate for your system.
If you do that, you will probably need to get 720 kB double density floppies, as I strongly suspect (but do not know) that that is what your PC20 has. Other people’s mileage has varied, but my experience writing DD images to HD disks has been okay on PC hardware (miserable on LIF drives, for whatever reason), but I have not had good luck writing DD images to HD disks specifically on USB floppy drives.
That said, the only real limitation of DOS 3.3 for use with CF drives on that hardware is going to be its 32 MB max partition size limit. While this may mean you lose a lot of the card’s storage space … for that machine, a couple of 32 MB partitions is probably more storage than you’ll ever need. Keeping in mind that it was designed to be operable with a single 720 kB disk and more or less conveniently operable with two 720 kB disks, you can see that a couple of 32 MB partitions is going to be just fine.
I’m not concerned with partition size. I doubt i need 32 Meg. Honestly, the only reason i wanted DOS 5 was because apparently FDISK on 3.3 can’t write the MBR. I can do that by hand with debug, so I guess it’s a small thing.
I installed IBM DOS 3.3 on a CF card on an IBM 5150 (from 360 kB factory floppies), and I don’t recall building the partition table or the master boot record being a problem, but it’s been a long time.
I would recommend getting a GoTek hardware floppy emulator. It’s a pretty straight forward process, plug in the GoTek as you would a floppy drive, write your images on a USB drive that you’d plug into the GoTek, select your current image from the front panel buttons and that’s it.
I used one of those with my Amiga 500 and it works perfectly. It even emulates the actual speed and sound of a floppy drive. I also got a nano USB stick so it’s almost flush with the panel. But, offcourse, you can replace it with a USB card reader if you like to tinker a bit.
