Subject: Re: 3.5" floppy drive in IBM XT?

From: Joe <[email-masked]>
Date: Mon Apr 14 07:19:44 2003

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

---

From: J Forbes <[email-masked]>
Date: Mon Apr 14 12:58:18 2003

----- Original Message -----
From: "Joe" <[email-masked]>
To: <[email-masked]>
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.

2.88m as appropriate.  The 360k drive has an asterisk on it, just like 

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

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From: "Fred Cisin (XenoSoft)" <[email-masked]>
Date: Mon Apr 14 13:59:17 2003

> >button.  The 3.5" drives from the PS/2 series were labelled 1.44m or 

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.

> >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

---

From: "Fred Cisin (XenoSoft)" <[email-masked]>
Date: Mon Apr 14 14:14:01 2003

> > >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.