VOGONS


First post, by LadyAIluros

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Kind of what it says. I have a 486 with AMIBIOS that asks for the HDD settings in the BIOS instead of autodetecting them. The platter drive I have in there now has the stats written on it, but what do I put in for a CF card drive? I know that DOS tops out at 512MB (the smallet card I could find was 2GB, I might try to patition it in Mac Disk Utility) but none of the 46 supplied settings come close. I already use 47 - User Supplied for the drive I have now, are there Clyn/Hea/WPCom/LZone/Sect nubers for this use case? The idea is is to set the CF drive as D: and use it to move software on and off the machine because wow is DOS networking a pain.

Thanks!

Reply 1 of 5, by douglar

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CF devices are IDE devices and are usually very flexible when it comes to Cylinder, Head, Sector configurations. You can use type 47 and put in anything that adds up to less than your total capacity ( and is less than your bios limits, probably 528MB) and it will probably function on your system. The big problem with randomly selected C,H,S values is that if you lose your settings, you can't read the data from the HD unless you reenter the same values and if you take the device to a contemporary system, it likely won't be readable, since it will insist on using values that are native to the drive, while the CF native settings are quite often not compatible with early 1990's BIOS.

I do sneaker net and I use EZ-Drive on my boot disk. It is able to autodetect most devices from the removable CF slot D: on bootup.

Consider using EZ-Drive version 9.09W if you are using windows 98. It supports FAT32.

Consider using EZ-Drive version 9.03W if you are using DOS 5. It is limited to 2GB volumes.

Here's a link to drive overlay software: https://www.vogonsdrivers.com/index.php?catid=19

Here's a review of common BIOS CHS limitations: https://www.vogonswiki.com/index.php/Storage# … age_Limitations

Reply 3 of 5, by weedeewee

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You might find the information on this website helpful .
https://www.win.tue.nl/~aeb/linux/Large-Disk-4.html

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Reply 4 of 5, by Thermalwrong

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You can boot up from a floppy disk then run IDEINFO to get the C H S values for a CF card 😀
It can be downloaded from here still: http://www.users.on.net/~fzabkar/IDE-identify/
That's what I do for my ~386 class systems where they don't support auto detect or LBA, and I don't want to run XT-IDE or overlay software.

Reply 5 of 5, by douglar

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LadyAIluros wrote on 2022-10-31, 20:36:

Cool! (My contemporary system is a Mac too which add yet another level of complexity to this!)

Yeah, you are going to need your retro PC to mount the CF with the same geometry as a modern OS would, and your motherboard BIOS probably won't support that, even if you know what values to enter into the BIOS drive table.

You need to get something on there that autodetects the storage device.

You got 3 options:

  1. Install drive EZ drive overlay software on your boot device. Likely means reformatting it. The drive overlay loads before the OS and patches your BIOS to support modern LBA addressing. Then it detects and mount your sneaker net CF device correctly, overriding whatever you enter in the BIOS drive table.
  2. Purchase a legacy commercial BIOS enhancement like a "SIIG ISA Bus EIDE BIOS Upgrade Card". This is a rom mounted on an ISA card that does similar things to the Drive overlay software without the headache of installing the drive overlay software. Sometimes these legacy solutions are limited to 8.4GB or 32GB , depending on when they were produced. Make sure you configure your motherboard to shadow your option rom in RAM for best performance.
  3. Roll your own option rom by burning XTide Universal BIOS to an eeprom and putting it on a board that supports option roms, usually an old network adapter. Takes some practice to work out the kinks in the process if you've never done it before. https://www.xtideuniversalbios.org/ https://www.youtube.com/watch?v=pCdQ6MWnNpU

If you need to read devices formatted on a contemporary OS, you are going to need an OS on your retro PC that supports FAT32, such as Win98.

If you want to use DOS 6 or older, make sure you partition and format the CF device on your retro PC for FAT16 volumes before putting data on them. You will be limited to 2GB volumes.