source for disk packs

[David Cortesi]

The National Museum of Computing (TNMoC) at Bletchley Park (http://www.tnmoc.org/, [needs]... blank disk cartridges — does anyone know of a source?

What pops to mind is that The Computer History Museum (computerhistory.org) has a fair number of those, dozens. Quite possibly TNMoC has already established relations with CHM. If they haven't, they should. Museums often swap artifacts, and I have no doubt that the UK outfit has spares of things CHM would love to have in exchange for some disk packs.

[Stewart]

Thanks David, I will make enquiries about any existing relationships
with CHM.

As you say we may have something that could benefit other museums,
and v.v.

Cheers
Stewart

[Peter Vaughan]

In regard to us sourcing some disk packs... We have a number of DEC RK05 disk packs which appear from the outside to be identicle to the 2315 disk packs and I know several disk manufacturers used the 2315 format around the same time (1964/1965). They are from various OEM manufacturers (BASF, SCOTCH).

Does any one know if these are compatible with the 2315 packs. They certainly load into the 1130 and all the holes on the underside centre metalwork and the slots in the rim are the same but I suspect there may be issues regarding oxide types, sector lengths, disk thickness etc. Has anyone actually tried an RK05 disk pack in the 1130?

Also are the IBM packs pre-formatted or can they be formatted on the 1130?

We are some way off in attempting to have the disk drive working (or actually powering up the machine for that matter) but just looking ahead.

Thanks

Peter

[Bob Flanders]

AFAIK, They should be identical.

IBM sold the RAMKIT drives to other manufacturers including DEC so the cartridges should work assuming there is no other degradation over time.

Further, the 1130 can init a pack, so when you get it working you should have storage.

Regards,
Bob

[Ross Patterson]

I distinctly remember that the Stuyvesant HS 1130 had several Scotch and BASF disks.  At the time, I didn't know any better and just assumed that was normal :-)

Ross

[John R Pierce]

On 07/11/11 2:01 PM, Ross Patterson wrote:
> I distinctly remember that the Stuyvesant HS 1130 had several Scotch
> and BASF disks. At the time, I didn't know any better and just
> assumed that was normal :-)
>

at Chi, we used a pile of brands of disk packs. I seem to remember a
lot of Dysan, BASF and some other brand I can't remember. we used the
500kword 1130 format single platter drives, and we sold a lot of 5 and
10 platter 10-20MB 14" removable disk pack beasts that emulated a bunch
of 2310 disk packs at once, or one big one and an extended area on the
rest of the pack. I forget who's drives we were using, memorex, data
something. They were like RP04 or something drives with an 1130
compatible controller built into the 2130

heh.
http://www-03.ibm.com/ibm/history/exhibits/1130/1130_4513PH04.html

--
john r pierce N 37, W 122
santa cruz ca mid-left coast

[Jeff Jonas]

>> I distinctly remember that the Stuyvesant HS 1130
>> had several Scotch and BASF disks.

Wow, I don't remember such details of the platters.
I think I mostly handled IBM branded ones
so they were never confused with the PDP11's RK05s across the hall.
Happily, the contractor's disk washing-machine handled all brands.

> at Chi, we used a pile of brands of disk packs.
> I seem to remember a lot of Dysan, BASF and some other brand I can't remember.
> we used the 500kword 1130 format single platter drives,
> and we sold a lot of 5 and 10 platter 10-20MB 14"
> removable disk pack beasts that emulated a bunch of 2310 disk packs at once

I have no photos or manuals for the Calcomp DS-12 I used.
It was an 11 platter / 20 surface 14" diskpack
that connected directly to the SAC (storage access channel).
Each disk surface was the equivalent of a 2-sided 2310 platter.
Without any drivers, it emulated 4-5 platters (disk 0-4 or 1-4)
but in banks of top 5 surfaces, next 5, etc.
I think the 5 platters was a DM2 limitation.
There were modes to access all surfaces if drivers were installed.

I seem to remember favoring Nashua brand diskpacks.

> heh.
> http://www-03.ibm.com/ibm/history/exhibits/1130/1130_4513PH04.html

One Cooper Union system had a dual unit
and the HUGE 1133 mux cabinet just for that.
It was nice to decommission the all that with the diskpack,
which was not only faster but more fun to watch
thru the clear plastic cover!

-- Jeff Jonas

[Tom Watson]

If you are looking for 2315 style disk packs, you should note that they
come in several different models. The ones used on the IBM 1130 were 4
sector disk packs, which accommodated the 321 word/642 byte sectors (you
need to include the disk address that was written at the beginning of
the sector.

Many of the other machines that used 2315 disk packs in that era used
different sector sizes. A common one used 24 sector packs, which nicely
were formatted to be 256 bytes a sector. In a disk controller I used 24
sector packs, and divided them down to 6 sector ones, for 1024 byte
sectors.

I don't know what the sector counts were used on the various DEC packs,
but the 4 sector version wasn't used much outside the IBM 1130 worls as
I recall.

I had a friend that worked at a disk drive company (Caelus), which is
why I know a bit about these things, as well as designing a disk
controller in the 1975 time era. No micros then (unfortunately!).
...Tom Watson

--
Tom Watson Generic short signature
t...@johana.com I'm at home now

[Christian Corti]

On Mon, 11 Jul 2011, Peter Vaughan wrote:
> In regard to us sourcing some disk packs... We have a number of DEC RK05
> disk packs which appear from the outside to be identicle to the 2315 disk
> packs and I know several disk manufacturers used the 2315 format around the
> same time (1964/1965). They are from various OEM manufacturers (BASF,
> SCOTCH).

RK05 packs, especially the 16-sector ones, are getting very rare. If you
have 16-sector packs you are a very lucky man; keep them at a good place.

> Does any one know if these are compatible with the 2315 packs. They
> certainly load into the 1130 and all the holes on the underside centre
> metalwork and the slots in the rim are the same but I suspect there may be
> issues regarding oxide types, sector lengths, disk thickness etc. Has anyone
> actually tried an RK05 disk pack in the 1130?

They *do not* work. First, the number of sectors mismatch (12 or 16 for
the RK05, depending whether it's for a PDP11 or PDP8, and 8 sectors for
the 2310). Second, an RK05 has a different recording density, i.e. it's
the double-density version of a 2310. Only the DEC RK02 was single-
density, but it is even rarer than a 16-sector pack.

> Also are the IBM packs pre-formatted or can they be formatted on the 1130?

They can be formatted on an 1130, no problem. OTOH I have several dozens
of 2315 packs for the 1130, but I'm probably on the wrong side of the
pond. I also have soft-sectored packs for HP 7905/7906 and 24-sector packs
for HP 7900 (and even one 32-sector pack for an EAI hybrid computer,
IIRC).

Christian

[John R Pierce]

On 07/12/11 1:53 AM, Tom Watson wrote:
> If you are looking for 2315 style disk packs, you should note that they
> come in several different models. The ones used on the IBM 1130 were 4
> sector disk packs, which accommodated the 321 word/642 byte sectors (you
> need to include the disk address that was written at the beginning of
> the sector.

indeed, that same size disk pack was used quite a lot on early 70s
minicomputers by DEC and Data General with a 2.5MB format too. Were
those the Diablo 33 or something? DEC RK05 and lotsa others?

[John R Pierce]

On 07/12/11 2:13 AM, Christian Corti wrote:
> They *do not* work. First, the number of sectors mismatch (12 or 16
> for the RK05, depending whether it's for a PDP11 or PDP8, and 8
> sectors for the 2310). Second, an RK05 has a different recording
> density, i.e. it's the double-density version of a 2310. Only the DEC
> RK02 was single- density, but it is even rarer than a 16-sector pack.

This is all starting to gel some old memories.... at least some
versions of the Diablo 3x series could be jumpered internally for the
low density 2310 format, and with the right disk packs and data
formatter, read/write 1130 compatible disks, as we used these on the Chi
box with complete media interchange (assuming both drives were
reasonablly well aligned).

[Peter Vaughan (TNMOC)]

--------------------------------------------------
From: "Christian Corti" <3...@gmx.net>
Sent: Tuesday, July 12, 2011 10:13 AM
To: <ibm...@googlegroups.com>
Subject: Re: [IBM1130] Re: source for disk packs

>> Does any one know if these are compatible with the 2315 packs. They
>> certainly load into the 1130 and all the holes on the underside centre
>> metalwork and the slots in the rim are the same but I suspect there may
>> be
>> issues regarding oxide types, sector lengths, disk thickness etc. Has
>> anyone
>> actually tried an RK05 disk pack in the 1130?
>
> They *do not* work. First, the number of sectors mismatch (12 or 16 for
> the RK05, depending whether it's for a PDP11 or PDP8, and 8 sectors for
> the 2310). Second, an RK05 has a different recording density, i.e. it's
> the double-density version of a 2310. Only the DEC RK02 was single-
> density, but it is even rarer than a 16-sector pack.
>

My disk manuals are at the museum so... Am I right in thinking the slots cut
in the inner underside rim determine the sector start positions and thus the
number of sectors per track / cylinder?

I did compare an RK05 pack from a PDP11 with the IBM pack that came with our
1130 system and I could not tell any difference, same number of slots in the
rim, including a double slot which I assume is how it finds the start
sector.

Or is there some other method to identify how many sectors per track the
disk pack is configured for.

>> Also are the IBM packs pre-formatted or can they be formatted on the
>> 1130?
>
> They can be formatted on an 1130, no problem. OTOH I have several dozens
> of 2315 packs for the 1130, but I'm probably on the wrong side of the
> pond.

I'm in the UK (Bletchley Park), where are you based? Stuttgart perhaps if my
Googling skills are working correctly.
Perhaps we could come to some arrangement to get some disks?

- Peter

[John R Pierce]

On 07/12/11 12:35 PM, Peter Vaughan (TNMOC) wrote:
> My disk manuals are at the museum so... Am I right in thinking the
> slots cut in the inner underside rim determine the sector start
> positions and thus the number of sectors per track / cylinder?
>
> I did compare an RK05 pack from a PDP11 with the IBM pack that came
> with our 1130 system and I could not tell any difference, same number
> of slots in the rim, including a double slot which I assume is how it
> finds the start sector.
>
> Or is there some other method to identify how many sectors per track
> the disk pack is configured for.

no, thats exactly it. that style of disk formatting is known as 'hard
sectored'.

but, i thought the RK05 was the later higher density 2.5MB disk pack
(effectively double density) with 16 sectors per track, while the
2310/2315 used on the 1130 was the original 1.2MB (1MB usable on the
1130) version, and had 8 sectors/track? There was an earlier RK0?
(03?) that was the 1.2MB size, but it wasn't long in the market.

[Al Kossow]

On 7/11/11 8:43 PM, John R Pierce wrote:

> at Chi, we used a pile of brands of disk packs.

You're the first person I've heard of that was at CHI.
Frank McConnell ended up with some of the documentation
from the company. I've put some of it up at
http://bitsavers.org/pdf/chi

We were trying to figure out what happened to the company or
where these docs originally came from. We thought they may have
been from the service manager (Bob Wilcox?)

do you still have anything (docs, promo literature..) from CHI?

I guess CHI and GA were the two main companies to spin off hardware
from the 1800/1130 architecture?

Here is what I was able to piece together of the history a couple
years ago

----

Computer Hardware, Inc.
Vertical Systems
Willcox Services

--

James P. Lennane

"After receiving his master's degree in mathematics from the
University of Detroit, Mr. Lennane joined the International
Business Machines Corporation in 1964, spending two and a
half years as a scientific systems engineer and a salesman.
He then founded Computer Hardware Inc., which produced clones
of the I.B.M. 1130 and 1800 mid-size computers, and in 1973
founded System Integrators, which sold publishing systems
to small newspapers using the clone computers. The company
broke into the big time in 1980 with a $9 million sale to
The Los Angeles Times."

CHI built an expansion box for the 1130 (CHI-1114) and an
internal core memory add-on (CHI-1106).

CHI designed the 2130 and 2131, extended 1130's in '74-'75.
An expanded model (CHI-3230) was developed in the late 70's.

The assets of CHI appear to have been acquired by Vertical
Systems, Inc / Bob Willcox in the early 80's. As of 1976,
Willcox was western regional service manager for CHI. An extended
version of the 3230 with up to 2mb of memory was developed
in the early 80's.

VSI designed a follow-on system called the System 85
converting much of the discrete TTL logic to PALs and
gate arrays. It is unknown if
any of the redesigned systems were ever sold.

Willcox Services was still supporting CHI/VSI systems through
the late 80's.

[John R Pierce]

On 07/13/11 1:37 PM, Al Kossow wrote:
> do you still have anything (docs, promo literature..) from CHI?

I hung onto a glossy color multipage flier for the 2130 for the longest
time, but I think it got purged when we last moved in the mid 90s. At
least, I haven't been able to find that file drawer full of oddities
from the 70s (I had a Cray-1 early complete technical reference manual,
other strange stuff like that).

> I guess CHI and GA were the two main companies to spin off hardware
> from the 1800/1130 architecture?

there was another. I'm trying to remember the name, Meta4 or
something? Their machine emulated several different architectures via
microcode, I never saw one. I seem to recall hearing that the Chi
machine was several times faster and a more complete total emulation
down to the XIO level.

[Peter Vaughan]

Since I last posted I've had a chance to check all the RK05 disk packs we have at the museum and contrary to what I said earlier, all the packs have a different number of slots cut in the inner rim to the IBM pack (RK05 have 12, 2315 have 8).

So it looks like none of the packs we have will be compatible... so I'm still looking for some suitable media.

- Peter

[Christian Corti]

I'll see what I can do. Perhaps we can part with some disks, depending on
the contents and condition. But that can take some time.

Christian

[Peter Vaughan]

Thanks Christian.

There is no hurry as we are a long way off (many many months) actually needing some disk packs, I was just seeing what might be available.

I'll post again when we are getting close to needing any.

Regards

Peter