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5150 Compact flash formatting

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    Originally posted by Blaze8088 View Post
    QEMU/KVM from libvirt under Manjaro Linux, probably a weird choice, but I already knew how to pass the CF as an HDD under it and wasn't sure how to do that when we tried PCEM.
    I would swear that I was able to do this using QEMU on a MacOS machine, IE, creating a bootable disk image from complete scratch. It was months ago so my memory is a tad sketchy but I think the one thing that may have differed from your procedure is I didn't try mapping the media (in my case an SD card because I'm using an SD->IDE adapter) directly to QEMU but instead made a "raw format" disk image file roughly the size of the SD and then dd-ing it to the SD after I'd done all the needful in the VM. (IE, booting from a floppy image, FDISK-ing, format /s-ing, etc.) I probably have a spare SD card lying around, I guess I could try re-doing it and make sure I'm not forgetting having to boot from the gotek to do the initial partitioning or whatever.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot


      where are you located? Are you lacking in floppy media? Floppy drives? which?


        Originally posted by erikarn View Post
        where are you located? Are you lacking in floppy media? Floppy drives? which?
        Media, but I don't want to have to use floppies as a crutch.


          You know what would make this whole process easier? If we just patched XT-IDE BIOS to print out the damned geometry that it detects, so we have a hope in heck of faking it.

          Who is the XT-IDE maintainer these days? I can submit a patch for it to print out CHS at boot, and then it's super trivial at that point to craft up the partition table to populate to make it boot. I used to have to do this back in the day when it came to LILO (linux bootloader) and various BIOSes idea of LBA versus CHS addressing modes..


            Originally posted by Blaze8088 View Post

            Media, but I don't want to have to use floppies as a crutch.
            ok, so as I just posted about - the problem here is that you don't know the geometry that XT-IDE is detecting the flash drive as, so you can't easily craft up a suitable partition table layout that DOS is happy with in order for all the boot stages to be happy.

            The trick is knowing the geometry in advance.

            Now, the UNFUN part of this is that sometimes the BIOS will quite happily use a /different/ geometry than what the CF card reports - it could speak LBA to the drive, and decide upon its /own/ CHS layout for MS-DOS and legacy boot applications. This quite frequently tripped up things in yesteryear. In fact, I re-discovered (and then remembered!) this when I installed a CF adapter in my 386 here rather than a whole XT-IDE setup - the geometry that the BIOS detects the drive as? Is not the same that's listed for that drive in the datasheet. Either the drive lied, or the data sheet is wrong, or the BIOS is recent enough to know about LBA and is making it "easier" for DOS to use the larger disk.

            In any case, the solution is to either know the precise geometry being presented by the drive -> XT-IDE (or general BIOS) -> BIOS -> MS-DOS boot blocks, and then craft up a suitable partition table in a virtual machine or other setup to match said geometry, OR you boot DOS on the drive yourself.

            Also note - MS-DOS 3.1 doesn't know about the DOS 6.2 FAT16 partition table, and it won't let you delete unknown drives. So, I ended up having to boot a DOS-6.22 boot disk on 360k media with fdisk to delete the partition, then boot MS-DOS 3.1 from a second/third 360k disk to partition and install the OS.

            With all that said - if you're in the bay area, I'm happy to provide you boot media to work around this nonsense. It really will be easier doing this on the 5150 itself rather than trying to guess drive geometry.


              Originally posted by erikarn View Post
              You know what would make this whole process easier? If we just patched XT-IDE BIOS to print out the damned geometry that it detects, so we have a hope in heck of faking it.
              No need, The XUB issues the " Identify Device " command, There is a tool on the XUB binaries website called "". Run it and it will report the results. Or one could look up the Manufacture data sheet for the CF card if available.


                Originally posted by Blaze8088 View Post
                Media, but I don't want to have to use floppies as a crutch.
                Then you're in for a lot of fun and games, As already mentioned a Gotek sounds like a good alternative though i've never had / used one.


                  The CHS geometry for the OP's CF card is in the datasheet for it:

                  cap | cyl | heads | sectors | model
                  256MB | 978 | 16 | 32 | THNCF256MMA

                  Presumably that's what the XUB BIOS is detecting, so for QEMU you'd presumably use something like:

                  qemu-system-i386 -boot acd -m 16 -cpu 486 -fda "Tandy MS-DOS 3.3.IMA" \
                  -device ide-hd,drive=ide0,cyls=978,heads=16,secs=32 -drive file="256MB.dsk",format=raw,if=none,id=ide0

                  (I just tested the above and was able to boot dos, FDISK the image file, and make it bootable with a format. Unfortunately the ZIP'ed version of the resulting file is about 310k, just a teeny bit over the forum's size limit. But it should be easy enough to recreate.)

                  Thinking about the time I had it "just work" when I DD'ed a partition from QEMU onto an SD card the card I was using in the SD->IDE adapter was over 8GB (yes, a waste for an XT but it's what I had lying around), I'm thinking that may have worked without specifying a geometry because with a card that big it'd have to use LBA natively at the BIOS level and, presumably, QEMU and XUB had compatible translation algorythms?
                  My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs Also: Blogspot