The twist in the various cables are not a standard feature, but, rather, an
IBM-ism cooked up to allow the drives to be jumpered identically, irrespective
of their physical unit number assignment, i.e. only on the basis of their
position on the cable. My esdi drives work fine on a PC without the twist and
in combination with a WD ESDI controller.
The twist is in a different position on the cable, and involves a different
number of wires, depending on whether it's a floppy or hard disk cable.
Of all the various drive types I've fooled with, the ESDI types seemed to work
with the least hassle and confusion of any, when put in the PC environment.
SCSI was the only type that even came close.
Dick
----- Original Message -----
From: "Clint Wolff (VAX collector)" <vaxman_at_qwest.net>
To: <classiccmp_at_classiccmp.org>
Sent: Friday, April 06, 2001 8:54 PM
Subject: Re: pertec interface
>
> IIRC, the 34 conductor control cable has (or may have) a twist
> in it similiar to a floppy cable, but incompatible. I had a lot
> of trouble with an ESDI drive that I could get to work. Oddly
> enough, the floppy drives didn't work either :)
>
> clint
>
> On Fri, 6 Apr 2001, Richard Erlacher wrote:
>
> > ESDI uses a 34-conductor control cable, and a 20-conductor data cable, both
> > similar to what's used on ST506/412.
> >
> > The only widely used interface I know of that actually uses TWO 50-conductor
> > cables is the Pertec controller/formatter interface.
> >
> > Dick
> > ----- Original Message -----
> > From: "Jeff Hellige" <jhellige_at_earthlink.net>
> > To: <classiccmp_at_classiccmp.org>
> > Sent: Friday, April 06, 2001 6:06 PM
> > Subject: Re: pertec interface
> >
> >
> > > >This sounds more like ESDI to me. If memory serves that was a two
> > > >cable system.
> > > >RLL and MFM were too, now that I think about it, although not 50 pin
cables.
> > > >I'm betting ESDI.
> > >
> > > The only true ESDI system, not counting the IBM DBA interface
> > > used in some of the PS/2 series, that I have here is in my MicroVAX
> > > II and it had daul Maxtor XT-8380E's installed. Full height 5-1/4"
> > > drives of 380meg each. I pulled one of them out to replace it with
> > > the TK50. Anyway, the cables for the drives are the same width as
> > > MFM/RLL drives: 34 and 20 pins. This is verified by comparing it
> > > directly to a Tandon TM-502. Wasn't ESDI an outgrowth of the ST-506
> > > drives/interface?
> > >
> > > Jeff
> > > --
> > > Collector of Classic Microcomputers and Video Game Systems:
> > > Home of the TRS-80 Model 2000 FAQ File
> > > http://www.geocities.com/siliconvalley/lakes/6757
> > >
> > >
> >
> >
> >
>
>
Received on Fri Apr 06 2001 - 23:29:40 BST