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dongfeng
August 8th, 2006, 12:46 PM
This card was in my dead IBM XT, connected to a 10MB Seagate ST-412 hard drive.

It is a "Xebec" controller, is marked IBM 1816101 and is dated SEP-16-83.

My question is, what other hard drives does it support? I've been offered three 20MB drives; a Seagate ST-225, Tandon TM262 and a NEC D5125.

Click for high-res photo of the front (http://www.howard81.co.uk/upload/vcf/xt/xt_controller01.JPG)

Click for high-res photo of the back (http://www.howard81.co.uk/upload/vcf/xt/xt_controller02.JPG)

Luke
August 8th, 2006, 10:55 PM
Only 10 Meg drive compatible with ST-412.

dongfeng
August 8th, 2006, 11:05 PM
Okay, then I might pass on those drives. Do you want the details for them, Luke?

modem7
August 9th, 2006, 03:42 AM
There are other versions of these Xebec 8-bit controller boards.
If you want to keep your XT 'IBM pure', try to get one of the IBM versions (that is, made by Xebec for IBM) that has a DIP switch block on it. That version supports types 1,2,13 and 16 drives. The ST-225 drive for example is a type 2 drive.

Luke
August 9th, 2006, 04:37 AM
This is the 1st version with support for type 1 only.
I have the same controller.

ST-412
-----------------
Cylinders............306
Heads...................4
Sector/track.........17
Precompensation..128
Landing Zone.......319
Bytes/Sector.......512

WD12
-----------------
Cylinders............306
Heads...................4
Sector/track.........17
Precompensation..296
Landing Zone
Bytes/Sector.......512

WD10 (I'am not sure if it's WD10. In TH as '1 0 M B 5 . 2 5 IBM')
-----------------
Cylinders............306
Heads...................4
Sector/track.........17
Precompensation..128
Landing Zone
Bytes/Sector.......512

I think that there are many more HDDs, but how much of 'em this controller can support?

These 2 WDxx have no Landing Zone... would Xbec handle 'em?
And could Xbec handle WD12 with different WP?

And one another question:
I have ST-225 and the best controller support mode that equals with configuration to St-255 but it have 306 WP, ST-225 have 300 is that bad?

modem7
August 10th, 2006, 04:47 AM
These 2 WDxx have no Landing Zone... would Xbec handle 'em?
As far as the controller is concerned, it has a type 1 drive fitted. Therefore any utilities that park the heads will issue a command to move the heads to cylinder 305.
If a drive with more than 305 cylinders is fitted, that means that the heads will probably get parked on a data cylinder. Thus the effect is the same as not having parked the heads.

modem7
August 10th, 2006, 05:03 AM
I have ST-225 and the best controller support mode that equals with configuration to ST-255 but it have 306 WP, ST-225 have 300 is that bad?
Let's look at the situation of an ST-225 connected to your 'type 1 only' board.

The ST-225 (a type 2 drive) is expecting to have WPC activated from cylinders 300 to 615. The board (believing it has a type 1 drive attached) will turn on the ST-225's WPC from cylinder 128 onwards.
Thus between cylinders 128 and 300, the ST-225 will have its WPC activated when it should not. I would thus expect some read/write errors in those cylinders, probably in the cylinder range of 128 to 200, with more errors appearing the closer the heads are to cylinder 128.
How often would the errors occur? I don't know. It might only be one error per one thousand read/writes.

Luke
August 10th, 2006, 05:33 AM
And can you say something about last cilinders in t1 drive?
Is Cyl 303 and 302 used?

modem7
August 18th, 2006, 04:18 PM
And can you say something about last cilinders in t1 drive?
Is Cyl 303 and 302 used?
So for the late reply. Somehow I read your question but failed to come back to reply.
The ST-412 has 306 cylinders. The landing zone (the cylinder where the heads are parked) is 305.
And so yes, cylinders 302-304 would be used - as data cylinders.

alker
February 20th, 2007, 08:37 AM
Hello,

I have many XT's, MFM / RLL controllers and disks.. but I try now for hours and hours to get an original Seagate ST-506 drive with 5MB to work on a XT.

Isn't there a possibility? Which controller should I use / which settings? It seems that the drive is working; it also low-level formats the drive (with a WD1002-wx1 controller) but on MS DOS 5.0 FDISK it shows 2 drives all the time?!?!.. and I cant fdisk the drive..

any experiences with the original 5mb Seagate baby that started it all?

Luke
February 20th, 2007, 08:54 AM
As far I know ST-506s never were mounted in IBM XTs and PCs.

I have DTC controller that would handle 5 Meg ST-506 drive, but I don't have such an old drive, but it should work.
Your controller - WD1002-wx1 don't support 5 Meg drives.

turtlewax
November 19th, 2009, 06:59 PM
I am looking for a MFM controller & cables for someone. If you have one that will work with 10MB MFM drive please let me know.

Maybe if price is right, a whole computer IBM PC or XT with above hardware.

dongfeng
November 20th, 2009, 04:43 PM
Wow, 2006!

I have loads of 10MB cards... but I am in the UK. Probably easier to get one from someone Stateside :)