7 Sep
2016
7 Sep
'16
10:18 a.m.
From: Paul Koning
Some IBM systems ... have a "2315" drive
which is an RK05.
Yeah, I think that was the original source of these packs. The Diablo 30/31
drives (used on the RK11-C controller before the RK05 was created) were
designed to use 2315 packs.
From: Tony Duell
My intention was to put the hub on a spare spindle ..
put the platter
on, turn it round by hand and use a lever-type dial gauge to get
minimum run-out.
One of the people I buy PDP-11 parts from reports that he actually did this
(using the exact procedure you describe) BITD. Apparently there's some
multi-platter pack that has the same exact platter as the RK05 (2315) pack,
and he had some damaged RK05 packs, and moved platters from the bad
multi-platter pack to the RK05's.
Noel
7 Sep
7 Sep
10:26 a.m.
On Sep 7, 2016, at 1:18 PM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
...
At least by visual appearance, the RP03, IBM 1311/2311, and IBM 2314 all seem to have
RK05-like platters.
paul
From: Tony Duell
My intention was to put the hub on a spare
spindle .. put the platter
on, turn it round by hand and use a lever-type dial gauge to get
minimum run-out.
One of the people I buy PDP-11 parts from reports that he actually did this
(using the exact procedure you describe) BITD. Apparently there's some
multi-platter pack that has the same exact platter as the RK05 (2315) pack,
and he had some damaged RK05 packs, and moved platters from the bad
multi-platter pack to the RK05's. 
10:51 a.m.
----- Original Message -----
From: "Noel Chiappa" <jnc at mercury.lcs.mit.edu>
To: <cctalk at classiccmp.org>
Cc: <jnc at mercury.lcs.mit.edu>
Sent: Wednesday, September 07, 2016 1:18 PM
Subject: Re: RK05 packs
From: Paul Koning
============================
FWIW Burroughs also used drives/platters like this with their small systems (B80 - B1800);
ISTR that they were ~ 5MB but 32 SPT instead of 12 or 16; unfortunately I dumped all of
mine long ago.
http://www.ricomputermuseum.org/Home/equipment/burroughs-b800
m
Some IBM systems ... have a "2315"
drive which is an RK05.
Yeah, I think that was the original source of these packs. The Diablo 30/31
drives (used on the RK11-C controller before the RK05 was created) were
designed to use 2315 packs.
From: Tony Duell
My intention was to put the hub on a spare
spindle .. put the platter
on, turn it round by hand and use a lever-type dial gauge to get
minimum run-out.
One of the people I buy PDP-11 parts from reports that he actually did this
(using the exact procedure you describe) BITD. Apparently there's some
multi-platter pack that has the same exact platter as the RK05 (2315) pack,
and he had some damaged RK05 packs, and moved platters from the bad
multi-platter pack to the RK05's.
Noel 
10:51 a.m.
FWIW Burroughs also used drives/platters like this
with their small systems
(B80 - B1800); ISTR that they were ~ 5MB but 32 SPT instead of 12 or 16;
unfortunately I dumped all of mine long ago.
I can remember when the Inmac catalogue (that dates me...) told you
to count the number of notches in the hub, subtract 1 (for the index
notch) and order the appropriate pack. I can't remember which ones
were listed.
Didn't the DEC RK01 use 8 sector packs? Something certainly did.
-tony
11:45 a.m.
On 9/7/16 11:21 AM, Paul Koning wrote:
That would fit the IBM 2315 if indeed it used one
sector notch for each sector (it has 8 per track).
and 100 TPI
Original Diablo drives were also 100 TPI, and used silver colored heads, moving to 200 TPI
and the more
common white ceramic heads.
Apparently, the 100 TPI Diablo heads are extremely difficult to find today. I remember all
the 100 TPI
Diablo drives at a friend's company getting converted to 200.
11:46 a.m.
On Sep 7, 2016, at 2:45 PM, Al Kossow <aek at
bitsavers.org> wrote:
On 9/7/16 11:21 AM, Paul Koning wrote:
TPI, as in "transitions per inch"?
I vaguely remember that the 1311 (20 sectors of 200 digits each per track) used silvery
colored heads. I wonder if those are the same. They were pretty sturdy; one day when we
had a hydraulic leak, the FE just cleaned heads and pack with isopropyl alcohol, fixed the
leak, and put the drive and pack back into service.
paul
That would fit the IBM 2315 if indeed it used one
sector notch for each sector (it has 8 per track).
and 100 TPI
Original Diablo drives were also 100 TPI, and used silver colored heads, moving to 200
TPI and the more
common white ceramic heads.
Apparently, the 100 TPI Diablo heads are extremely difficult to find today. I remember
all the 100 TPI
Diablo drives at a friend's company getting converted to 200.
2:04 p.m.
On 9/7/16 11:46 AM, Paul Koning wrote:
TPI, as in "transitions per inch"?
tracks per inch
I vaguely remember that the 1311 (20 sectors of 200
digits each per track) used silvery colored heads. I wonder if those are the same. They
were pretty sturdy; one day when we had a hydraulic leak, the FE just cleaned heads and
pack with isopropyl alcohol, fixed the leak, and put the drive and pack back into
service.
2311 is 100 tpi, 2314 is 200
http://s3.computerhistory.org/groups/ibm-1311-2311.pdf has a nice picture of the 2311
heads
6:34 p.m.
On Wed, Sep 7, 2016 at 1:18 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
Yeah, I think that was the original source of these
packs. The Diablo 30/31
drives (used on the RK11-C controller before the RK05 was created) were
designed to use 2315 packs.
I have one RK11-C (as well as RK11-D, RKV11-D and RK8E) and I used to
have a Diablo 30, but it was badly damaged in a (backed-up sewer)
flood 25 years ago and discarded. It's on the restoration list with
the other Unibus gear...
-ethan
3027
days inactive
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days old
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