14 Apr
2003
14 Apr
'03
5:58 a.m.
----- Original Message -----
From: "Joe" <rigdonj(a)cfl.rr.com>
To: <cctech(a)classiccmp.org>
Sent: Monday, April 07, 2003 6:12 PM
Subject: 3.5" floppy drive in IBM XT?
I picked up an old IBM XT today and it has a
3.5" floppy drive in
it (and it works!) Anybody ever heard of this? The drive
has
it's own controller card and both it and the drive appear to be IBM
parts. )I haven't pulled everything apart to be sure.) FWIW the
computer also has a FH 5 1/4" floppy drive and a HH 5 1/4" 10 Mb hard
drive with a Seagate logo on the front of it. Anybody know if
this is an original XT hard drive or a replacement drive? It's been so
long since I've seen an original XT with the 10 Mb drive that
I don't remember much about it.
Joe
I have a highly original late production XT, with the 640k system board,
720k hh floppy, 360k hh floppy, and full height IBM 20mb hard drive.
Interesting features include a Y cable to power both floppy drives from
the PSU connector (Y cable has black wires, and a cloth tag with IBM
part number 6480173). Also, the 720k drive has a plain blue eject
button. The 3.5" drives from the PS/2 series were labelled 1.44m or
2.88m as appropriate. The 360k drive has an asterisk on it, just like
on the optional AT 360k drive. Apparently the IBM convention for 5.25"
drives was that if it was a full height floppy, drive then it was 360k,
if it was a half height drive it was assumed to be 1.2M, unless it had
an asterisk, then it was 360k.
Mueller's book says that the 640k system board, XT 20M hd, half height
360k drive, and 720k drive were introduced in April, 1986.
Hope this helps solve the mystery....
--
Jim
Visit the Selectric Typewriter Museum!
http://www.mindspring.com/~jforbes2
14 Apr
14 Apr
12:19 a.m.
At 10:07 PM 4/13/03 -0700, Jim wrote:
I have a highly original late production XT, with the 640k system board,
720k hh floppy, 360k hh floppy, and full height IBM 20mb hard drive.
Interesting features include a Y cable to power both floppy drives from
the PSU connector (Y cable has black wires, and a cloth tag with IBM
part number 6480173). Also, the 720k drive has a plain blue eject
button. The 3.5" drives from the PS/2 series were labelled 1.44m or
2.88m as appropriate.
Yes, that sounds exactly like the drive in this machine.
The 360k drive has an asterisk on it, just like
on the optional AT 360k drive. Apparently the IBM
convention for 5.25"
drives was that if it was a full height floppy, drive then it was 360k,
if it was a half height drive it was assumed to be 1.2M, unless it had
an asterisk, then it was 360k.
This 360K drive only has IBM marked on it. But I have seen a number of external drives
with the asterisk on them. The X drives for the IBM P70s all seem to be marked that way.
Thanks for the info.
Joe
6:59 a.m.
New subject: Labelling of drives (was: 3.5" floppy drive in IBM XT?
>I have a highly original late production XT, with
the 640k system board,
>720k hh floppy, 360k hh floppy, and full height IBM 20mb hard drive.
>Interesting features include a Y cable to power both floppy drives from
>the PSU connector (Y cable has black wires, and a cloth tag with IBM
>part number 6480173). Also, the 720k drive has a plain blue eject
>button. The 3.5" drives from the PS/2 series were labelled 1.44m or
>2.88m as appropriate.
PS/2's ALSO had 3.5" drives with a blue eject button labelled 720K.
The 720K was out for a while before 1.4M or 2.8M existed. All IBM
3.5" drives with unlabelled button (IN THOSE DAYS) were 720K.
The 360k drive has an asterisk on it, just like
>on the optional AT 360k drive. Apparently the IBM convention for 5.25"
>drives was that if it was a full height floppy, drive then it was 360k,
>if it was a half height drive it was assumed to be 1.2M, unless it had
>an asterisk, then it was 360k.
Full height drives could also be 720K, although that was never used by IBM
in the U.S.
There were 1.2M full height drives (never used by IBM), but they are now
rather rare.
Half height 360K drives existed BEFORE the existence of 1.2M.
The Qume 142 (one of the worst drives EVER) HH drives used in the Jr and
in the "Portable PC" did NOT have asterisks.
LATER, when IBM started selling ATs with 1.2M drives, they started to put
asterisks on 360K HH drives for the AT.
Thus, a HH drive with an asterisk is a 360K that came out after the 1.2M.
An IBM HH drive without an asterisk could be:
a 360K (from before the 1.2M)
a 1.2M
an aftermarket drive of any size
7:14 a.m.
New subject: Labelling of drives (was: 3.5" floppy drive in IBM XT?
> The 360k drive has an asterisk on it, just like
> >on the optional AT 360k drive. Apparently the IBM convention for 5.25"
> >drives was that if it was a full height floppy, drive then it was 360k,
> >if it was a half height drive it was assumed to be 1.2M, unless it had
> >an asterisk, then it was 360k.
The 720K HH 5.25" drives in the IBM PC/JX (also available with 3.5")
also did not have an asterisk.
7923
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7923
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3 comments
3 participants
participants (3)
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cisin＠xenosoft.com -
jforbes2＠mindspring.com -
rigdonj＠cfl.rr.com