Substituting DSHD for DSDD disks (or DS2D if you prefer)

CuriousMarc curiousmarc3 at
Tue Jan 26 23:10:27 CST 2016

You make me feel lucky. I have all 3 (almost, I have the low density HP 9121 rather than an HD 9122 so I can use it on my HP 85)... Haven't restored or even powered up the recently acquired HP 9895 yet, but the HP 82901A and the HP 9121D now work great. Quite low capacity (270k?) due to the weird LIF formatting, formats 35 tracks but uses only 33, out of the 40. I wonder why. I don't know anything yet about the 8" HP 9895 and its encoding. I thought they were surprisingly high capacity (1.2 MB?) considering their age. Am I right? 

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Eric Smith
Sent: Tuesday, January 26, 2016 2:48 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Substituting DSHD for DSDD disks (or DS2D if you prefer)

On Tue, Oct 27, 2015 at 7:47 AM, Paul Berger <phb.hfx at> wrote:
> I would really
> like to get a HP 9895 8" drive but they seem to be few and far between.

Same here. And I'd like to get an 82901M 5.25" drive, and a 9122C HD 3.5".

I was surprised to learn that the 9895, while it supports standard IBM
3740 single-density format, uses an HP-proprietary M2FM double-density format.

More information about the cctalk mailing list