Uncreative Labs

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

I have some useful information to report for people who are planning on running an 8-bit SCSI adapter in their XT. I have tried about four different cards, and I think the road to SCSI is not as easy as many may think. The biggest problem comes along if you plan to boot off a SCSI drive. Many 8-bit cards do not have an on-board BIOS. Additionally, sometimes the BIOS is designed to only operate in an AT bus system. The Future Domain TMC850IBM and any TMC850M with a BIOS of version 8.4 or greater will not boot in an XT. The Seagate ST01/02 is a stripped down version of the TMC850 card. It only supports two devices, and only the last revision supports non-seagate hard disk drives. Additionally, those cards do not have an ASPI driver and therefore do not support CD-ROM drives. I finally settled on an NEC/Trantor T128 card. It boots in an XT, and has drivers from around the early 90s or so, so support is pretty decent for most devices. It is ideal to run these SCSI cards without an IRQ if the devices supports it, as throughput will double. I previously got 150KBps on my Maxtor drive, but now I'm getting 300KBps. I hope to double that to 600KBps when I upgrade my XT to 10MHz. However, I believe that the Future Domain TMC850M with BIOS V8.2 is the way to go. Those cards have software updated as recently as 1997. I am trying to get a new ROM for my card as we speak. There are a few Future Domain cards on ebay right now, but the seller has be unable to confirm the BIOS version for me as of yet. That's all I have to say about that.

Guest

I have an 8 bit board -somewhere, no bios
and a seagate st01? card from tee fred.
planned to try it in a xt system but never got around to it.

I have a few mfm drives buries somewhere but they may be dead by now, so getting a drive running on an 8088 system may be impactical at this late date.
what scsi drives can I use on a seagate controller?
can I fdisk a larger drive as a, say 100 meg drive?

Posted: Wed Oct 26, 2005 8:52 pm

Yes you can format up to 2gb with a SCSI controller BUT a non-bios card may need an interface driver to get access to your hard drive Sad

You can technically use up to an 8gb drive in an XT but you can only access 2gb of the drive.

Good Luck

Joined: 02 Oct 2004 Posts: 594 Location: Western NC

Quote:

Yes you can format up to 2gb with a SCSI controller BUT a non-bios card may need an interface driver to get access to your hard drive. You can technically use up to an 8gb drive in an XT but you can only access 2gb of the drive.

I thought you could access the entire 8GB as long as you partitioned off the drive to 2GB-or-less sections?

Posted: Thu Nov 03, 2005 12:19 am

Quote:

I thought you could access the entire 8GB as long as you partitioned off the drive to 2GB-or-less sections?

I thought the same but I couldn't get it to happen for some reason

Guest

I have a TMC-850mer with boot rom .

and a TMC-850M with out the rom chip .

Pulled from a 486 that was running an auto salvage yard .

TmC-850mer , has dr dos ,or pc dos I can't remember .

I could toss it in a system and find out .

What are you willing to pay or trade for it ????

BK ...

Guest

the 2 gb limit ( 2.048m) is a dos limit, and affects dos and the dos under w 95a.
the later fat 32 dos-w95b and win 98 will work with larger partitions.
It is possible and likely that a w95b or w 98 boot disk ( converted to a 720k)
may NOT boot on a 8088 because of its memory requirements.

there were manjy bios limits with drives, the 528m was a 2/3/486 mb bios limit.
but an xt relies on the controller bios .

the wd mfm/rll bioses may
I seem to recall, do have a similar limit like 1024/16/17 (not 63 sectors)
or 26 sectors in the case of a rll card.

scsi bioses in 2./3.486 bypass/ignore the mb bios limit as they are not entered in the bios.

the bios chips in biosed 8 bit scsi cards or the drivers for the UN-bios versions
may also have drive size limits.

It;s my hope that the seagate st01? card will work with a scsi card that I have,

Joined: 22 Oct 2005 Posts: 61 Location: sunny AZ

win95 needs a 386, win98 needs a 32 bit 486 (not sx)

at least that's what they claim when you try to boot the floppy on an older machine

Guest

i did expect problems and thought that to be the case, but the
8088 boards are buried behind the big pilke
all I have is 2 mini 386 boards in a box with other smaller cards.
the rest is in tre rafters and buried.

I suppose they would maks stealth xt's
my last xt project was trying to set up a cpm86 system.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Hey NOUSERNAME! Tell me more about your TMC850MER. What's the version on the ROM chip?

Posted: Wed Nov 09, 2005 4:57 am

Anonymous Coward wrote:

Hey NOUSERNAME! Tell me more about your TMC850MER. What's the version on the ROM chip?

Are you the same anonymous @ vintage-computer ? I think someone @ vintage-computer forum has the image of TMC850 bios.

Guest

Anonymous Coward wrote:

Hey NOUSERNAME! Tell me more about your TMC850MER. What's the version on the ROM chip?

Well, I can't read the printing on the chip , but some one put a lable on it .

Which say's 7.0 ... I'm gonna toss it in a 486 and see

what it say's when It boot's up ... I'm pretty sure the rom chip

Will work with either card .

BK

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Yes, I am the same as the user at Vintage-Computer.com. I have recieved images of the V8.0 and V8.2 of the BIOS. This is really good news for people who want to install SCSI drives on their XTs, as the TMC-850M is the best SCSI adapter that you can get for you PC/XT. You should be able to use either of these BIOS images on any TMC850 card (TMC850IBM, TMC850MEX, TMC850MER...etc). These cards pop up on ebay fairly often. If you need a copy let me know.

Maybe you should find a way to dump the image of the 7.0 too...you know, for archival purposes.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

I finally found a TMC850M with a V8.2 bootROM. YES!

Joined: 18 Oct 2004 Posts: 54 Location: Nottingham, England

Hi,
I've been playing with scsi stuff just recently, although more modern stuff. However, do you think either of the 8-bit cards here would work in a 5150:
http://cgi.ebay.co.uk/4-x-ISA-SCSI-cards-2-x-internal-2-x-external_W0QQitemZ6829744694QQcategoryZ90716QQrdZ1QQcmdZViewItem
Question