TESTFDC usage

Chuck Guzis cclist at sydex.com
Wed Jun 6 18:03:27 CDT 2007


On 6 Jun 2007 at 18:17, Dave Dunfield wrote:

> I also don't find ED very relevant to archiving vintage computer diskette
> images - are there any systems in need of such attention that use ED as
> their standard disk format?

I do have a few IBM PS/2 distros on ED.  I am aware of a few 
companies selling into the PS/2 market for whom 2.88M was the 
distribution medium.  The Teac drive that will handles these in 
either media-sense or host-specified mode is the FD-235J.  

IBM used (IIRC) host-side density control on much of the PS/2 line, 
so you *could* format anything from 720K to 2.88M on a plain-Jane 
DS2D disk.  Maybe the result wasn't entirely reliable, but it could 
be done.

The "right" media is a barium ferrite formulation and has the density 
aperture closer to the bottom edge of the disk than do the DSHD 
diskettes.  If you stick one of these things in a 1.44MB-only drive, 
it appears as a DS2D.

As far as "PC drives", those Mitsubishi/NEC 360RPM drives ran MS-DOS 
2.10 on their host system (the flavor is sometimes called "DOS-V").  
Diskettes were generally formatted as 8x2x1024x77 or 8x2x1024x80; 
some of the CP/M formats used 256-byte sectors.  

Even Windows NT running on a 9801 supported that format--as does (in 
read-only mode) Windows XP/2000 today.  As far as Microsoft back in 
the day was concerned, the 9801 platform was a PC, just not a 
"Western" PC.  At one time, the 9801 platform owned something like 
70% of the PC market in Japan.

Hope I got this all correct.

Cheers,
Chuck




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