Subject: Re: 5.25" drive identification

From: Al Hartman <[email-masked]>
Date: Fri Apr 18 23:16:01 2003

> From: [email-masked] (DAVID L. ORMAND)
>
> I have been told (by an IT professional, take that
> for what it's worth) that 5.25" 360K drives have
> the latch handle on the left side of the drive, and
> the 1.2M drives have it on the right side.  All the
> drives I have in view right now, this is true.
>
> Anybody have a notion of whether this is absolutely
> true in fact?

You've already gotten an answer from others on the
list on this. LOL!

> It sure would make sorting drives easier than
> trying them out on an old peecee!  (Which actually
> needs to be done anyways, to test for
> functionality.)

A rule of thumb I use, but I won't swear is
universal... Is the LED color. USUALLY... Red LED
signifies 360k/180k Drives, and a Green LED signifies
1.2mb Drives.

And I also think that as for IBM Drives, the 360k at
one point were made with and Asterisk molded into the
front case. I could have this reverse. But, I seem to
remember some discussion (perhaps here) that someone
thought it was odd that IBM would start adding the
asterisk to 360k Drives, hence having some with and
some without, rather than just making all 1.2mb drives
with asterisks.

I may have this one reversed though.

But, I've used the LED color as a good indicator for
years.

Also, if you look at the jumpers on the logic board,
near the drive select jumpers... A 1.2mb drive should
have a Speed Select Jumper (SS) to select High speed
Data Transfer to work on AT-Standard Floppy
Controllers, and low speed (for what? I don't know...
Maybe to work on an 8in Drive Controller?)

So, that's another indication of whether the drive is
high or low density.

Regards,
Al Hartman
The New Yahoo! Search - Faster. Easier. Bingo
http://search.yahoo.com

---

From: "Fred Cisin (XenoSoft)" <[email-masked]>
Date: Sat Apr 19 13:47:00 2003

> signifies 360k/180k Drives, and a Green LED signifies

Like the faceplate color, that is one that TENDS to be correct, but with
exceptions.  Some of the earliest 1.2M had red LEDs, andsome of the later
360K drives had green.  But it would work for a rough sort, followed by
confirmation by model number.

> I may have this one reversed though.

No, YOU have it right; IBM did it wrong.  Once there were two similar
drives, there was a need for visual identification.  The RIGHT way to do
it would have been to put the added emblem on the NEW type, so that all of
the old ones would already be correctly labelled.  OR make two different
emblems, so that all emblemed drives would be labelled.

> But, I've used the LED color as a good indicator for

Glad it's worked for you, but there ARE exceptions.  The incorrect door
handle one worked for somebody (who had simply switched brands of drives
at the same time that they switched from buying 360K to buying 1.2M)

> Maybe to work on an 8in Drive Controller?)

NO!
At least a third of the 1.2M drives do NOT have a speed select.  It is for
whether the drive changes speed 300 v 360 RPM, NOT for data transfer
rate.  The data transfer rate of a 1.2M at "high" density IS the rate of
an 8" DSDD.  The two are indistinguishable, unless you count 77 v 80
tracks.

> So, that's another indication of whether the drive is

If a drive does both 300 RPM AND 360 RPM, then it is 1.2M
If a drive supports both 300 and 360 RPM, then the controller needs only
250K and 500K data transfer rates.  (Plus 125K bits per second if you want
to do 5.25" FM (150K bits per second with single speed 1.2M drives))

If a drive only does one speed, then it could be a 360K drive, OR it could
be a 1.2M that expects the controller to handle the difference.  The IBM
AT controller did 250K, 300K, and 500K bits per second data transfer
rates, and used single speed drives.
If the single speed is 300 RPM, then it is a 360K drive.
If the single speed is 360 RPM, then it is a 1.2M drive.

--
Grumpy Ol' Fred        [email-masked]

---

From: [email-masked] (Tony Duell)
Date: Sat Apr 19 16:26:00 2003

> signifies 360k/180k Drives, and a Green LED signifies

Again, not reliable. The 1.2M drive on this machine (orginal IBM) has a 
red LED. I think that for Teac drives, the LED colour was actually a 
customer-selectable option (red, yellow and green all exist, for all 
types of drives)

> some without, rather than just making all 1.2mb drives

It's more complicated than that. There are 2 types of IBM 360K 
half-height drives. The one that was used in the PortablePC and the PCjr 
does _not_ have the asterisk. The one that is used in the PC/AT does. The 
2 drives have other differences too -- they were made by different 
manufacturers normally (the PortablePC / PCjr one is a Qume, I forget who 
made the one for the PC/AT), and I suspect pin 34 changed between Ready 
and DiskChange.

No IBM 1.2M drive has the asterisk. 

This is really stupid (as others have pointed out) -- it would have been 
much easier and clearer to mark the 'new' type of drive -- the 1.2M one.

> Maybe to work on an 8in Drive Controller?)

No, the 8" controller would have wanted the higher speed too (360rpm).

IBM controllers always spun the 1.2M drive at 360rpm, which means they 
had to support a 300kbps transfer rate (==(360/300) * 250kbps) for 360K 
disks in 1.2M drives. The lower speed (almost never used) was to allow 
360K disks to be read at 250kbps on a suitable controller.

However, this jumper is also not a reliable indication of drive type. 
Many later drives have almost no jumpers at all, and SS would be one of 
the first to vanish as almost nobody used it. So there are 1.2M drives 
around without the jumper.

And some manufactuerers used common logic boards and even spindle motor 
PCBs for 360K and 1.2M drives. Which means there are 360K drives out 
there with the SS jumper.

-tony

---

From: "Fred Cisin (XenoSoft)" <[email-masked]>
Date: Sat Apr 19 20:10:01 2003

The beige faceplate on 360K is yellower than on 1.2M

360K has jumpers for drive 0,1,2,3; 1.2M has jumpers for A,B

360K has a screen that is usually white on black; 1.2M has a screen that
is white on blue.  (If it bluescreens, then the drive is a 1.2M)

---

From: "Jeffrey S. Worley" <[email-masked]>
Date: Sat Apr 19 22:20:00 2003

Boy, I'm so glad that is settled.  Now I know how to identify any 5.25"
mech just by the color of the faceplate and soldermask on the pcb.

Wow.  Why didn't I ever think of that?

Until this moment, I've been using silly things like model numbers,
testing, and something no one has yet mentioned:

	The step rate marked on the stepper in degrees.  Sometime this
can 	yield a clue.

Regards,

Jeff

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of Fred Cisin (XenoSoft)
Sent: Saturday, April 19, 2003 9:09 PM
To: [email-masked]
Subject: Re: 5.25" drive identification

---

From: Don Maslin <[email-masked]>
Date: Sat Apr 19 23:24:00 2003

> testing, and something no one has yet mentioned:

Don't you think that is a bit rudimentary?

> 	The step rate marked on the stepper in degrees.  Sometime this

Unfortunately, that is hard to find these days.  I cannot recall
seeing that on any half-high drive.
						- don

---

From: "Jeffrey S. Worley" <[email-masked]>
Date: Sun Apr 20 01:26:00 2003

I guess you missed the irony.

  Yes.  It is rudimentary and almost totally useless.  If you've handled
as many hundreds of drives as I have, you'd know that color, shape,
size, door-type, whatever, has no bearing.

I mean, you can guess from experience and be right more often than not,
but if a customer called me by phone and described a drive, I wouldn't
venture to say 40 or 80 track, high or regular density etc without
testing the drive myself. Barring a test, a model number would be the
only other way I'd swear to a drive's capacity.

Regards,

Jeff

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of Jeffrey S. Worley
Sent: Saturday, April 19, 2003 11:21 PM
To: [email-masked]
Subject: RE: 5.25" drive identification

Regards,

Jeff

---

From: [email-masked] (Tony Duell)
Date: Sun Apr 20 13:28:01 2003

> The beige faceplate on 360K is yellower than on 1.2M

:-) Only because the 360K drive is likely to be older...

> 360K has jumpers for drive 0,1,2,3; 1.2M has jumpers for A,B

Nonsense!. I've seen plenty of 1.2M drives with 4 drive select jumpers...

> is white on blue.  (If it bluescreens, then the drive is a 1.2M)

If my PERQ ever bluescreens I'll eat a PDP11 (I have a 5.25" 1.2Mbyte 
drive hooked up to the PERQ as a little hack. The PERQ, of course, has a 
white monochrome monitor).

That's quite apart from the fact that PC/AT machines (the most common 
place to find 1.2M drives) most certainly support MDA and CGA cards...

-tony

---

From: [email-masked] (Tony Duell)
Date: Sun Apr 20 13:32:57 2003

> testing, and something no one has yet mentioned:

The method I use is to hook the drive up to an exerciser and check for 
(a) the number of head steps between the limits (40 -> 360K, 80 -> 
possible 1.2M, but maybe a standard data rate only drive, giving 720K on 
a pC). And (b) the index timing -- can the thing give 6 index pulses per 
second (360rpm) or not?

I find this to be the most reliable way of distinguishing between 
different drives...

-tony

---

From: "Fred Cisin (XenoSoft)" <[email-masked]>
Date: Sun Apr 20 14:06:00 2003

On Sun, 20 Apr 2003, Tony Duell wrote:
> . . . 

I used to think that checking model number was reliable identification.  
Until I encountered a drive labelled TM 100-4, that turned out to be a
100-4M.  It actually was a serendipitous occurence, since I had been
having trouble finding any 100 TPI drives.

---

From: [email-masked] (Tony Duell)
Date: Sun Apr 20 16:25:01 2003

> having trouble finding any 100 TPI drives.

YEs. While the model number is a good guide, it's not always reliable. 
Particularly not when some mad hacker (like me) has been swapping bits 
between drives to configure the unit he needs. I might well move an 80 
cylinder head and stepper assembly onto a chasssis that once held a 40 
cylinder unit, and then not change the model number label.

The onyl way to be sure is to test the drive!

-tony

---

From: Don Maslin <[email-masked]>
Date: Sun Apr 20 21:11:01 2003

> I guess you missed the irony.

I think it may have been mutual, Jeff.
						- don

> only other way I'd swear to a drive's capacity.
<SNIP>

---

From: "Jeffrey S. Worley" <[email-masked]>
Date: Mon Apr 21 12:05:00 2003

Ah! Humor.  I had to look it up in Miriam Webster's to be sure.

Pardon my density. Pun intendted.

Regards,

Jeff

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of Don Maslin
Sent: Sunday, April 20, 2003 10:07 PM
To: [email-masked]
Subject: RE: 5.25" drive identification

<SNIP>

---

From: Tothwolf <[email-masked]>
Date: Mon Apr 21 14:11:00 2003

On Sat, 19 Apr 2003, Tony Duell wrote:

> > A rule of thumb I use, but I won't swear is universal... Is the LED
> > color. USUALLY... Red LED signifies 360k/180k Drives, and a Green LED
> > signifies 1.2mb Drives.
>

Panasonic 5.25" drives use a socket for the front panel LED, so it is
extremely easy to change the color. I've swapped out many amber LEDs in
their 1.2Mb drives for green ones. According to the company when I
requested technical docs for that particular series of drives, the LED
color was something a customer could specify when ordering drives.

-Toth

---

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---

From: Jeffrey Sharp <[email-masked]>
Date: Mon Apr 21 16:14:00 2003

This has been dealt with.  Move along, nothing to see here.

On Tuesday, October 16, 2001, Jo?l Weber wrote:
> ...

-- 
Jeffrey Sharp