18 Jan
2005
18 Jan
'05
8:31 a.m.
Fred Cisin wrote:
The early PS/2 drives did NOT have a sensor. They
would "successfully"
format a 720K diskette to 1.4M. (Reliability was less than perfect due
to 600 Oersted v 750 ) But then, when that disk was put into a
drive that had a sensor, the drive would have problems with it.
LOL! This brings back many memories. My friend and I had done this on his
PS/2 and thought we were laughing all the way to the bank... I even saw an
advertisement in Byte in the late 1980s hawking a 3.5" DSDD hole puncher that
could turn 720K disks into 1.4MB disks. I didn't want to shell out $29.95 for
the puncher so I started burning holes into my 3.5" disks with my soldering
iron :-D
So what was the catch? The devil, as they say, is in the details, and some of
the details are hidden in the advertising copy of the puncher: "We tested over
100 punched disks for over a month, writing and reading data. With the
exception of only one disk, THERE WERE NO FAILURES AT ANY TIME!" (emphasis not
mine). What's wrong with this picture? They continually wrote to the disks.
What I found in practice was that, if you kept writing to the disk, it did
indeed work. But leave the disk in storage for 6 months, and *poof*, your data
started to fade. As soon as I discovered this (by losing source code, argh!),
I copied the data off of my disks, covered up the holes I had burned with
stickers, reformatted the disks at the proper 720K, compressed the data, and
put it back on the disk :)
--
Jim Leonard (trixter(a)oldskool.org) http://www.oldskool.org/
Want to help an ambitious games project? http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/