"Bob Eager" wrote in message
...
On Fri, 25 Jun 2010 07:12:09 +0100, Roland Perry wrote:

In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

The important point about the ICL drum was that (like the real drums
before it) it had one head for each track, thereby reducing the seek time
to the electronic switching time. They were mainly used for paging, but I
seem to recall that the ICL ones were let down by a sluggish transfer
rate.

Real drums didn't use Winchester type heads IIRC.
They were drums so all the heads were the same and the surface speed was the
same, with disks the surface speed changes with the head position.


My first programming (around 1968) was done on hand-punched cards, which
I preferred to paper tape as it was both easier to edit and faster to
create (I could hand-punch cards faster than the CPS of the teletype
you'd use to make the paper tape).

Same here....my first three years (1970-73) were nearly all on punched
cards. I still have a few as bookmarks!

I learnt Fortran IV using a portapunch to make cards.
They were then sent to IC to be run in the batch system by post.
When they returned you had to debug them from the printout.
It could take a while.
That was a primary school, I lost the facility when I went to secondary
school as they didn't see computers as important. 8-(

In message , at 08:04:54 on Fri, 25 Jun
2010, "dennis@home" remarked:


"Bob Eager" wrote in message
...
On Fri, 25 Jun 2010 07:12:09 +0100, Roland Perry wrote:

In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

The important point about the ICL drum was that (like the real drums
before it) it had one head for each track, thereby reducing the seek time
to the electronic switching time. They were mainly used for paging, but I
seem to recall that the ICL ones were let down by a sluggish transfer
rate.

Real drums didn't use Winchester type heads IIRC.

True, they didn't float over the surface, and that's one reason the
capacity was poor.

They were drums so all the heads were the same and the surface speed
was the same, with disks the surface speed changes with the head
position.

The ICL "drums" I worked on were actually discs.

I learnt Fortran IV using a portapunch to make cards.
They were then sent to IC to be run in the batch system by post.
When they returned you had to debug them from the printout.
It could take a while.

I was the runner who took the cards from school each day to the
(different) college on my way home, and brought back the previous day's
output. Talking to the operators, and being allowed into the computer
room to help them, was one of the things that motivated me more than
just the programming.
--
Roland Perry

Roland Perry Inscribed thus:

In message , at
16:19:28 on Thu, 24 Jun 2010, John Rumm
remarked:
IIRC I bought my first HDD about '87. A "huge" 42MB seagate.

By around 1981 I was the UK distributor for the Micropolis range of
drives, which were originally in the same form factor as an 8" floppy
drive. The most capacious was 33MB, and cost about the same a small
family car.

One of my customers was the BBC newsroom, who bought one to store
digitised images to project behind the newsreader's head - to replace
the infamously unreliable slide projector they used to have. In those
days it was difficult to find people who thought they needed that much
storage (outside of a classic mainframe scenario).

Couldn't resist, :-)
I still have my first ever hard disk drive, purchased in 1983/4. It has
four 5.25" platters and a linear stepper driven head. A whopping 5Mb.
Well in was in those days ! It still functions, though its more of a
showpiece nowadays.

--
Best Regards:
Baron.

Andy Champ Inscribed thus:

dennis@home wrote:

Most drives rotated quite slowly and it took a lot longer to read the
data from a single drive than an array, the latency was the same.


I'd argue that drives rotate more slowly now.

No, really. They've gone from 3600 to 10000 RPM - but the capacity
has grown several orders of magnitude, so the speed is much lower in
proportion.

Andy

I would argue that that the speed has increased markedly simply because
the storage density has improved dramatically. 15K spindle speeds and
360Gb plus on a single platter. Add to that on board two way cache, on
some drives 32Mb, means that the bottleneck is moving back to how fast
the mainboard circuits can handle the data stream.

--
Best Regards:
Baron.

dennis@home Inscribed thus:



"Roland Perry" wrote in message
...

Somewhere I have an early "PROM", you programmed it by soldering
diodes in, and the foot-square PCB probably has a couple of dozen
bytes capacity.

I had a piece of PROM where you sewed wires through the ferrite rings
to program it. I lost it years ago which is a shame as people couldn't
believe it was a bit of computer.

A similar "core" based memory was used in a "Seeburg" Jukebox to store
record selections in the late fifties early sixties.

--
Best Regards:
Baron.

On 25 June, 07:57, "dennis@home"
wrote:

I had a piece of PROM where you sewed wires through the ferrite rings to
program it.

I doubt that very much indeed.

Ready-laced, and used as RAM (actually NVRAM), yes we've all got the
odd plane or two of that lying around. But PROM by intermittent
lacing? I doubt that very much indeed.

(I'm sure that someone somewhere did make this, I just doubt that
yours used lacing to program it rather than matrix-selected write
pulses.)

On 24 June, 23:36, "Jeff Strickland" wrote:

I remember drives that were sensitve to changes in orientation.

I had a rack server a month or two back that was sensitive to whether
it was the upper or lower slot in the rack.

As always, it turned out to be thermal. Some muppet had lost an
internal air deflector from the other machine, so it was running with
a hot spot on the top of its case. Place that at the top and it was
OK. Place that underneath and the drives in the server above got
cooked.

On Jun 25, 10:46*am, Andy Dingley wrote:
On 25 June, 07:57, "dennis@home"
wrote:

I had a piece of PROM where you sewed wires through the ferrite rings to
program it.

I doubt that very much indeed.

Ready-laced, and used as RAM (actually NVRAM), yes we've all got the
odd plane or two of that lying around. But PROM by intermittent
lacing? I doubt that very much indeed.

(I'm sure that someone somewhere did make this, I just doubt that
yours used lacing to program it rather than matrix-selected write
pulses.)

Sounds like core rope memory to me. The PROM content was defined by
the lacing pattern. The bit density was much greater than read/write
core.

MBQ

On Fri, 25 Jun 2010 09:50:13 +0000, Huge wrote:

On 2010-06-24, Bob Eager wrote:
On Thu, 24 Jun 2010 21:00:23 +0000, Huge wrote:

On 2010-06-24, Roland Perry wrote:
In message , at 14:20:35 on
Thu, 24 Jun 2010, Jules Richardson
remarked:
(and remember the days when you had to reformat the drive if you
changed its orientation, as otherwise it'd start spewing out errors
all over the place? :-)

No, I don't remember that, and I go back all the way to 1980

Pah. Newbie.

and drives
that were 10MB per platter.

Blimey. Huge capacity. There's a platter from a Xerox system hanging
on my study wall. IIRC, the drive was 20Mb and had 5 platters. I wish
I could remember what the capacity of the DEDS drive on the ICL 1900
series I learned RPG2 (spit) on was. About 5 Mb (?), with two platters
that had to be exchanged seperately, but in pairs, on a horizontal
spindle inside a *huge* grey crackle-finish enclosure.

Now I have 3.5 Tb of disk in mys study ...

The disks on the ICL 4130 at Kent

Ahh, KOS. Now, those were the days. Or perhaps not.

(I thought it was an NCR/Elliott 4130? Or were they subsumed into ICL?)

They were subsumed into ICL. All the manuals I bought had ICL on them.

(I bought them to work out how the multiprogramming hardware worked, so I
could (successfully) subvert it)



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On Fri, 25 Jun 2010 09:56:04 +0000, Huge wrote:

You sure it was a "platter"? Only, when I worked for ITT in around
1975/6 (on what became the Unimat 4080 telephone switch), the message
switches that we shared our computer room with definitely had drums that
were drum shaped. This kind of thing;

I'm sure, anyway. I saw them Bloody great vertically mounted platters,
big strip of heads. Functionally a drum.
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On Fri, 25 Jun 2010 08:04:54 +0100, dennis@home wrote:

"Bob Eager" wrote in message
...
On Fri, 25 Jun 2010 07:12:09 +0100, Roland Perry wrote:

In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

The important point about the ICL drum was that (like the real drums
before it) it had one head for each track, thereby reducing the seek
time to the electronic switching time. They were mainly used for
paging, but I seem to recall that the ICL ones were let down by a
sluggish transfer rate.

Real drums didn't use Winchester type heads IIRC. They were drums so all
the heads were the same and the surface speed was the same, with disks
the surface speed changes with the head position.

I never said otherwise (I said "like the real drums before it"). They
were however formatted with a larger number of sectors on the outer
tracks to make best use of packing density.

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On 25/06/2010 11:00, Huge wrote:
Having recently moved my aged mother from a 3 bed house to a 1 bed flat, I
am determined to throw all the junk out.

I hope you didn't mean that in the way that it reads!

Jon
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In article , Jon
Green writes

A low level reformat can sometimes help, but IME it usually only delays
the inevitable.

There's no such thing with modern drives. All you can do is zero it
(write zeros to every sector).

--
Mike Tomlinson

In message , at 10:00:38 on Fri, 25 Jun
2010, Huge remarked:
Having recently moved my aged mother from a 3 bed house to a 1 bed flat, I
am determined to throw all the junk out.

That's no way to speak about your mother!
--
Roland Perry

In article , Huge
writes

Having recently moved my aged mother from a 3 bed house to a 1 bed flat, I
am determined to throw all the junk out.

I did a similar thing 3 years ago. Just coming to the last of the piles
of boxes in the back bedroom.

--
Mike Tomlinson

In message , at 09:50:13 on Fri, 25 Jun
2010, Huge remarked:

(I thought it was an NCR/Elliott 4130? Or were they subsumed into ICL?)

I started on an ICL 4120 which was an Elliott design, but inside ICL by
late 60's.
--
Roland Perry

In message , at 11:53:13 on Fri, 25 Jun
2010, Bob Eager remarked:

I never said otherwise

Sometimes it's really hard for people on usenet to accept that a posting
is in agreement with theirs.
--
Roland Perry

In message , at 09:56:04 on Fri, 25 Jun
2010, Huge remarked:
In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

You sure it was a "platter"? Only, when I worked for ITT in around 1975/6
(on what became the Unimat 4080 telephone switch), the message switches
that we shared our computer room with definitely had drums that were
drum shaped.

Absolutely sure. It was in ICL's in-house computer room in Bracknell,
and I was one of those engineers allowed to wander around and look at
anything I wanted to. In the hope that one day, when it broke, I could
try to fix it. I say "day", more like "half an hour".
--
Roland Perry

In message , at 12:54:33 on Fri, 25 Jun
2010, Huge remarked:
It's a head-per-track disk. But I suppose
you could argue it's functionally the same as a drum.

No-one is denying that. But it looks like a platter (with a lot of fixed
heads), not a drum.

If you aren't careful, I'll start talking about delay-line memory ;-)
--
Roland Perry

In message
, at
02:48:57 on Fri, 25 Jun 2010, Andy Dingley
remarked:
I remember drives that were sensitve to changes in orientation.
....
As always, it turned out to be thermal.

Correct - that's all it is.
--
Roland Perry

In article , Ben C
writes

The whole point of a RAID is you populate it with eight _different_
drives, not 8 identical ones!

Ehhh? Complete crap.

--
Mike Tomlinson

In article
s.com, Andy Dingley writes

RAID has _never_ synchronised heads or spindles.

I'm not so sure. I know I have seen SCSI drives with a sync out pin,
and am fairly sure I have seen RAID setups where those were all
connected to synchronise the drives. This would have been 15 or so
years ago though.

--
Mike Tomlinson

In article
s.com, Andy Dingley writes

A little later, and you're reduced to skip-diving to get the legacy
parts for it, whilst storage of similar size and performance is
sellign for tuppence ha'penny down the road at PC World.

The answer to that is to lay in spare parts at the same time as the
order for the RAID unit. Yes, it increases the initial cost, but at
least you know you have the spares available in five years' time.

--
Mike Tomlinson

In message , at 15:35:44 on Fri, 25 Jun
2010, Mike Tomlinson remarked:
A little later, and you're reduced to skip-diving to get the legacy
parts for it, whilst storage of similar size and performance is
sellign for tuppence ha'penny down the road at PC World.

The answer to that is to lay in spare parts at the same time as the
order for the RAID unit. Yes, it increases the initial cost, but at
least you know you have the spares available in five years' time.

The best RAID controllers build that in - they have one or two spare
drives configured in, that don't initially store any data, but can be
swapped in when needed.
--
Roland Perry

On 25/06/2010 16:04, Huge wrote:
Nor indeed, my precious collection of techno-junk. I expect somone, somewhere
will want it. As I said, the PDP11 and other assorted computing relics
already went to Bletchley Park.

Sadly, my beloved 11/70 went to the scrapper after it got damp in
temporary storage and wouldn't come out to play ever after. Corroded
boards and drives apart, there's just way too much wire-wrap to diagnose!

Along with a fair load of other techno-junk, I've still got the first
computer I owned, a Sharp MZ-80K. (Not the first one I programmed; that
was a mainframe, and doubtless Kingston Poly (as was) scrapped it many
moons ago.) It still worked when I last tested it.

Jon
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On 25/06/2010 15:10, Roland Perry wrote:
In message , at 12:54:33 on Fri, 25 Jun
2010, Huge remarked:
It's a head-per-track disk. But I suppose
you could argue it's functionally the same as a drum.

No-one is denying that. But it looks like a platter (with a lot of fixed
heads), not a drum.

If you aren't careful, I'll start talking about delay-line memory ;-)

Mercury, I should hope ... the One True DLM!

Jon
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On 25/06/2010 16:02, Roland Perry wrote:
In message , at 15:35:44 on Fri, 25 Jun
2010, Mike Tomlinson remarked:
A little later, and you're reduced to skip-diving to get the legacy
parts for it, whilst storage of similar size and performance is
sellign for tuppence ha'penny down the road at PC World.

The answer to that is to lay in spare parts at the same time as the
order for the RAID unit. Yes, it increases the initial cost, but at
least you know you have the spares available in five years' time.

The best RAID controllers build that in - they have one or two spare
drives configured in, that don't initially store any data, but can be
swapped in when needed.

Hot spares. And they're supplied under a contract where replacements get
delivered to you in a few hours. The maintenance contract pays for their
stockpiling of old drives. And if the small stuff really does disappear,
it copes with putting a larger drive in instead. (wastes the space, but
works).

On 25/06/2010 14:56, Mike Tomlinson wrote:
In articleBbednRHroYQSK7zRnZ2dnUVZ7rWdnZ2d@brightvie w.co.uk, Jon
writes

A low level reformat can sometimes help, but IME it usually only delays
the inevitable.

There's no such thing with modern drives. All you can do is zero it
(write zeros to every sector).

You can do a bit better than that. Manufacturers' tools that are doing
the zero-fill (SeaTools, etc.) also verify and remap where necessary,
using the pool of unallocated sectors. It's about as close to a "true"
LLF as you're going to get, these days.

Jon
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On 25/06/2010 16:02, Roland Perry wrote:
In message , at 15:35:44 on Fri, 25 Jun
2010, Mike Tomlinson remarked:
The answer to that is to lay in spare parts at the same time as the
order for the RAID unit. Yes, it increases the initial cost, but at
least you know you have the spares available in five years' time.

The best RAID controllers build that in - they have one or two spare
drives configured in, that don't initially store any data, but can be
swapped in when needed.

I suspect that Mike meant more than just the drives. If you're dealing
with mission-critical data, it's imperative to keep a hot spare RAID box
too, in secure storage away from the building, so that you can bring up
the data set ASAP after a RAID main board failure. There's absolutely
no guarantee that the drive set will work together in a different model
or make -- in fact, it's pretty-much certain they won't.

Yes, I'm assuming that any sensible sysadmin's doing verified regular
backups and off-site storing them, but bringing up a whole new RAID from
scratch, using backups, with a new disk set takes ages. If you can just
pull the drives, jam 'em into the hot spare and be up again in ten
minutes (to include config transfer) instead, you'll be the star of the
show.

Jon
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Andy Dingley wrote:
On 25 June, 07:57, "dennis@home"
wrote:

I had a piece of PROM where you sewed wires through the ferrite rings to
program it.

I doubt that very much indeed.

Ready-laced, and used as RAM (actually NVRAM), yes we've all got the
odd plane or two of that lying around. But PROM by intermittent
lacing? I doubt that very much indeed.

(I'm sure that someone somewhere did make this, I just doubt that
yours used lacing to program it rather than matrix-selected write
pulses.)


Before fusible link proms, you used diodes, switches or links on the boards.

Core stores are early forms of disk..really.

On 25/06/2010 17:03, Jon Green wrote:

I suspect that Mike meant more than just the drives. If you're dealing
with mission-critical data, it's imperative to keep a hot spare RAID box
too, in secure storage away from the building, so that you can bring up
the data set ASAP after a RAID main board failure. There's absolutely no
guarantee that the drive set will work together in a different model or
make -- in fact, it's pretty-much certain they won't.

Yes, I'm assuming that any sensible sysadmin's doing verified regular
backups and off-site storing them, but bringing up a whole new RAID from
scratch, using backups, with a new disk set takes ages. If you can just
pull the drives, jam 'em into the hot spare and be up again in ten
minutes (to include config transfer) instead, you'll be the star of the
show.

Once you're doing that you may as well have the second RAID (or rather
filer) mirrored from the first, and have a truly hot DR system.

Obviously there's redundant main boards in the raid setups too :-)

On 25/06/2010 17:28, Clive George wrote:
On 25/06/2010 17:03, Jon Green wrote:

I suspect that Mike meant more than just the drives. If you're dealing
with mission-critical data, it's imperative to keep a hot spare RAID box
too, in secure storage away from the building, so that you can bring up
the data set ASAP after a RAID main board failure. There's absolutely no
guarantee that the drive set will work together in a different model or
make -- in fact, it's pretty-much certain they won't.

Once you're doing that you may as well have the second RAID (or rather
filer) mirrored from the first, and have a truly hot DR system.

That'll work...so long as the backup RAID isn't totalled by the same
fire or power surge that nargled the primary!

It won't absolve you from having the hot (well, warm, since it's not
connected or running) spare and the backups off-site for full disaster
recovery.

So now you've got three sets of kit! Primary, local mirror, off-site
hot spare.)

Jon
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On 25/06/2010 18:22, Jon Green wrote:
On 25/06/2010 17:28, Clive George wrote:
On 25/06/2010 17:03, Jon Green wrote:

I suspect that Mike meant more than just the drives. If you're dealing
with mission-critical data, it's imperative to keep a hot spare RAID box
too, in secure storage away from the building, so that you can bring up
the data set ASAP after a RAID main board failure. There's absolutely no
guarantee that the drive set will work together in a different model or
make -- in fact, it's pretty-much certain they won't.

Once you're doing that you may as well have the second RAID (or rather
filer) mirrored from the first, and have a truly hot DR system.

That'll work...so long as the backup RAID isn't totalled by the same
fire or power surge that nargled the primary!

I did make the assumption that the backup RAID was at a different site :-)

It won't absolve you from having the hot (well, warm, since it's not
connected or running) spare and the backups off-site for full disaster
recovery.

So now you've got three sets of kit! Primary, local mirror, off-site hot
spare.)

Nah, just two - Primary, off-site hot spare/mirror.

On Fri, 25 Jun 2010 15:08:47 +0100, Roland Perry wrote:

In message , at 09:56:04 on Fri, 25 Jun
2010, Huge remarked:
In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

You sure it was a "platter"? Only, when I worked for ITT in around
1975/6 (on what became the Unimat 4080 telephone switch), the message
switches that we shared our computer room with definitely had drums that
were drum shaped.

Absolutely sure. It was in ICL's in-house computer room in Bracknell,
and I was one of those engineers allowed to wander around and look at
anything I wanted to. In the hope that one day, when it broke, I could
try to fix it. I say "day", more like "half an hour".

Connected via an SFC - a Sectored File Controller, I believe. I have
source code for driving it right here.....!

We used it as a 'fast' paging area, but it wasn't that marvellous, so I
think we gave up in the end, faster to use the ordinary disk as pages
often spilled from it to disk anyway. This was on a homebrew operating
system for the 2900.



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On Fri, 25 Jun 2010 15:04:19 +0100, Roland Perry wrote:

In message , at 09:50:13 on Fri, 25 Jun
2010, Huge remarked:

(I thought it was an NCR/Elliott 4130? Or were they subsumed into ICL?)

I started on an ICL 4120 which was an Elliott design, but inside ICL by
late 60's.

Yes, that was the detuned 4130. Main differences were a lot of
instructions implemented by software extracodes, and no multiprogramming
support.

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On Fri, 25 Jun 2010 15:25:43 +0000, Huge wrote:

On 2010-06-25, Roland Perry wrote:
In message , at 09:56:04 on Fri, 25
Jun 2010, Huge remarked:
In mid 70's I worked on ICL drives, including something they called a
"drum", which was a single-platter mounted vertically.

You sure it was a "platter"? Only, when I worked for ITT in around
1975/6 (on what became the Unimat 4080 telephone switch), the message
switches that we shared our computer room with definitely had drums
that were drum shaped.

Absolutely sure.

It appears that ICLs weird storage topology terminology was unknown to
me. Not surprising. I was a MUMPS programmer roped in to help rewrite
ATV's payroll system in RPG2 (spit) and port it from a 1904S (I think)
to a 2903. That was my only exposure to ICL kit - I left shortly
afterwards to return to my beloved PDP11s and trying to weigh flying
crisps.

I think that's right, though....ICL did keep a lot of old terminology
around. As well as inventing new stuff - like the CPU becoming an OCP
(Order Code Processor)

[note to self...must get on with the mostly-completed 2900 simulator]



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"Jon Green" wrote in message
...
On 25/06/2010 17:28, Clive George wrote:
On 25/06/2010 17:03, Jon Green wrote:

I suspect that Mike meant more than just the drives. If you're dealing
with mission-critical data, it's imperative to keep a hot spare RAID box
too, in secure storage away from the building, so that you can bring up
the data set ASAP after a RAID main board failure. There's absolutely no
guarantee that the drive set will work together in a different model or
make -- in fact, it's pretty-much certain they won't.

Once you're doing that you may as well have the second RAID (or rather
filer) mirrored from the first, and have a truly hot DR system.

That'll work...so long as the backup RAID isn't totalled by the same fire
or power surge that nargled the primary!

Or the more likely software fault.


It won't absolve you from having the hot (well, warm, since it's not
connected or running) spare and the backups off-site for full disaster
recovery.

So now you've got three sets of kit! Primary, local mirror, off-site hot
spare.)

Four, the off-site kit should be a replicate of the main site so you can use
it to provide the same service.

We had fully functioning SystemX exchanges inside containers so we could
park one outside and exchange, connect up the trunks, etc. and away you go.

On Fri, 25 Jun 2010 19:58:08 +0100, Tim Streater wrote:

In article ,
Bob Eager wrote:

On Fri, 25 Jun 2010 15:04:19 +0100, Roland Perry wrote:

In message , at 09:50:13 on Fri, 25
Jun 2010, Huge remarked:

(I thought it was an NCR/Elliott 4130? Or were they subsumed into
ICL?)

I started on an ICL 4120 which was an Elliott design, but inside ICL
by late 60's.

Yes, that was the detuned 4130. Main differences were a lot of
instructions implemented by software extracodes, and no
multiprogramming support.

Could you define what's meant by "multiprogramming support" in this
context?

Two operating modes - user and executive. Or did I get it wrong and the
4120 had that too? Enter user mode with the EXIT instruction, and system
call back with the EXEN instruction...

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

In message , at 15:02:48 on Fri, 25 Jun
2010, Huge remarked:
If you aren't careful, I'll start talking about delay-line memory ;-)

Well, I've *seen* some in the Science Museum.

I've got one in my attic somewhere.
--
Roland Perry

In message , at
16:47:11 on Fri, 25 Jun 2010, Jon Green remarked:
If you aren't careful, I'll start talking about delay-line memory ;-)

Mercury, I should hope ... the One True DLM!

No, the one I have is acoustic.
--
Roland Perry