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Larger Disks in my 486DX2

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First post, by twitch86

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Hi Guys,

im having a hard time setting up my 486 Midi Adventure Station.

The board is a " SIS 85C461" with an AMIBIOS and with 8mb Ram and im using it with a noname Floppy / IDE Controller Card.

I bought two CF Adapters and a SD Adapter and hoped to be able to use these as a Harddrive.
My BIOS actually recognized ALL CARDS up to 8GB if i do the autodetection. BUT if i try to install DOS they are formatted with 500mb. Why is that, if the BIOS actually seems to see the real size?

I tried several Bootmanagers. All the Ontrack Versions detect my Cards but it takes ages for the blue Splashscreen to appear after reboot (Sometimes 5min or more) so this is not an Option. EZ-Manager runs perfectly BUT only recognizes my 1GB CF Card and nothing else.. If i put a 2GB or 4GB in it tells me no IDE drives detected...

Any Ideas? Why cant i install larger disks if the Bios sees them properly? HELP!

Or i will have to live with 1GB 😁

P.S. This is my only VLB mainboard so i would love to use this... maybe a bios update?!

Reply 2 of 32, by HanJammer

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FAT16 has 2 GB partition size limit (for sector sized at 512).

For drives larger than ~500MB BIOS or device driver has to support HDDs >1024 cylinders or LBA mode.

Your answer: XT-IDE, just burn it to some EEPROM, put it on ISA network card and you are ready to go 😀
It solved all CF-related problems in my Philips 386SX (it won't boot from CF at all - no matter what I was doing).
It supports some cool additional features too (like drive autodetection).
Also it's not like you are doing anything that your hardware wasn't capable of back in the day, so I find this solution very clean.

Also consider installing FreeDOS which has FAT32 support allowing for much larger partitions.

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Reply 3 of 32, by Caluser2000

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EZDrive DDO works fine for using a 4gig hdd in my 386DX25. It's small and quick. Install it and select Type 2 in the Bios hdd settings.

There's something definitely wrong if Ontrack takes 5minutes to load. It was only a few seconds on my 386 before I replaced it with EZDrive.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 4 of 32, by twitch86

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Thank you all for your answers.

1. I tried a win98 boot disk, with fdisk which should enable large file support but it didnt. it didnt even give me this splash screen/ promt to inform about larger partitions.
so i went back to Bios and it seems it is limited bei den 16 heads thing....

2. I tried all 3 or 4 Versions of Ontrack that i could get my hands on. One comes with IBM one with Seagte und the others with an Ontrack splashscreen...
The loading time happens with CF and SD Adapter... so maybe bei IDE Controller Card?!

3. i have never heard of XT-IDE but thank you for this tip i will google that!

Reply 5 of 32, by twitch86

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EDIT:

it seems like my 2x 2GB and 1x 4GB Card all have some issues... when i try to format them in windows. i cleaned them with diskpart... are there any recommodations for 2 or 4gb cards which work fine with EZ ?

Reply 6 of 32, by HanJammer

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Caluser2000 wrote:

EZDrive DDO works fine for using a 4gig hdd in my 386DX25. It's small and quick. Install it and select Type 2 in the Bios hdd settings.

There's something definitely wrong if Ontrack takes 5minutes to load. It was only a few seconds on my 386 before I replaced it with EZDrive.

I can confirm that EZDrive also worked in my 386SX but compared to XT-IDE BIOS it's a nuisance.

twitch86 wrote:

(...)

3. i have never heard of XT-IDE but thank you for this tip i will google that!

XT-IDE: http://www.xtideuniversalbios.org/

Also: https://www.youtube.com/watch?v=B0tp-I-iJ1k

You can get it in form of Compact Flash - ISA adapter, IDE controller, or you can simply burn it yourself (or ask somebody to do it for you) on some 27256 EPROM (EEPROM ideally) and install it on any network card which has bootrom socket (which is what I would recommend - you can always use the network interface for MTCP and telnet to some BBS-es from DOS which is fun!). Configuration is as easy as enabling the bootrom in network card's config, setting correct address and setting HDDs in BIOS to None.

Want to buy AT cases, motherboards and other vintage stuff? My Items for Sale
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Reply 7 of 32, by Caluser2000

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Re XT-IDE I use one of these on my XT Turbo clone. https://monotech.fwscart.com/XT-IDE_Bootable_ … 4_19478732.aspx

I've met the guy and he is a great person and I've had no issue with the card at all. Some of his stuff is on e-bay but contacting through the site saves a few dollars. He's away for a week or so.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 8 of 32, by twitch86

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i found this old card in my 286 - will this work for XT-IDE?

Do i have to set jumpers or something?

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Reply 9 of 32, by canthearu

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It will probably work.

You will need to work out how to enable the boot rom on the card, and you will need a chip (atmel AT28C64B-15PU will probably work) and a way of programming the BIOS chip.

I originally was flashing my Atmel flash chips using an actual XT-IDE card, but recently got a TL866II Plus programmer to do it instead as it far more flexible.

Reply 11 of 32, by canthearu

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You could use either a 27C or a 28C, as the pinout and reading signaling are the same. The only real difference will be with the programming, which you can do in your eeprom programmer.

Reply 17 of 32, by Tronix

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twitch86 wrote:

my old 286 tells me: Option - Rom at C800:0000 ERROR

Before burn any ide_xxx.bin to flash you need run xtidecfg.com utility. Then LOAD ide_xxx.bin, then SAVE it back.
This will expand the image file size and fix the checksum.

Reply 18 of 32, by GigAHerZ

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canthearu wrote:

You could use either a 27C or a 28C, as the pinout and reading signaling are the same. The only real difference will be with the programming, which you can do in your eeprom programmer.

Nope, the pinout is different. Be careful!

"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!

Reply 19 of 32, by canthearu

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GigAHerZ wrote:
canthearu wrote:

You could use either a 27C or a 28C, as the pinout and reading signaling are the same. The only real difference will be with the programming, which you can do in your eeprom programmer.

Nope, the pinout is different. Be careful!

Please explain. In what way is it different, for a reading only application?