"John Rumm" wrote in message
o.uk...

Some early implementations of RAID level 2 tried this. Bit level splitting
of data over some drives and applying FEC to generate check and correct
bits on parity drives.

Its not used these days since for obvious reasons - and it kind of went
against the whole raid philosophy in the first place, so calling it
"proper RAID" is a Dennis'ism really.

Show me where I called it a proper RAID?
You are reading stuff that hasn't been written.

PS what do you think are the obvious reasons they died out?

In article , Paul Bird
scribeth thus
Roland Perry wrote:
In message , at
08:23:48 on Wed, 23 Jun 2010, Jon Green remarked:
Don't think a reformat will fix them either as some on t'internet think.

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

It won't actually write a "low level" format pattern to the drive, but
will serve to mark some sectors as "bad". However, it won't stop the rot
spreading.

. . . and the rot can spread remarkably quickly. Hours in my experience.

PB

Well this one was doing odd things for about a day and then went down
very quickly, mainly odd screen freeze's...
--
Tony Sayer

On Thu, 24 Jun 2010 09:08:51 +0100, dennis@home wrote:

"John Rumm" wrote in message
o.uk...

Some early implementations of RAID level 2 tried this. Bit level
splitting of data over some drives and applying FEC to generate check
and correct bits on parity drives.

Its not used these days since for obvious reasons - and it kind of went
against the whole raid philosophy in the first place, so calling it
"proper RAID" is a Dennis'ism really.

Show me where I called it a proper RAID? You are reading stuff that
hasn't been written.

You said:

"Ah well that was probably in the days of proper RAIDs.
The ones where it was done bitwise across the disks and all the spindles
and heads were synchronised. They were expensive."

We repeat: it wasn't RAID. It wasn't Inexpensive.




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"Bob Eager" wrote in message
...


We repeat: it wasn't RAID. It wasn't Inexpensive.

Inexpensive is not a quantitive measure.
What is inexpensive to one person is expensive to another.
You can't actually define inexpensive so its not going to win the argument.

The main differences were in the distribution of controllers, they used to
be boards full of complex electronics with cheaper disks without
controllers. Disks with controllers (e.g. SCSI) were the expensive option
and didn't work with bitwise arrays. Therefore the array which shared the
controller and used dumb drives was the inexpensive option (note that no
drives were inexpensive then, some were a few hundred dollars cheaper but
still cost as much as a car these days).

It was only when disk controllers became a chip or two and were integrated
into the drive that they became cheaper and that had as much to do with
decreasing physical size as with integrating electronics.

That's the trouble with kids, they just don't know what happened in the
past. ;-)

"tony sayer" wrote in message
...
In article
s.com, Weatherlawyer scribeth thus
On Jun 22, 9:03 pm, tony sayer wrote:
Bought a new drive, Western digital IDE 250 GB back in March this year.

Bl^^dy thing has gone tits up already..

Most everything is backed up but there were a few things that were
forgotten about and now they are a lot more important;!.

There was a thread somewhere detailing some of the ways to recover data
apart from commercial outfits costing a lot of money. PC won't recognise
it apart from make and model number and thats as far as it goes..

Anyone any suggestions?..

Also anyone any suggestion as to a reliable make of drive as it seems to
me there're all getting rather bad!..

The police will supply any data they have about you but it incurs a
search fee. And a lot of moidering.

Don't believe all you read;!..


But how did they get involved with problems with your drive? Did
friends have an accident backing up?

Pardon?..


I think its a word play on PC.

"John Rumm" wrote in message
o.uk...
On 24/06/2010 09:08, dennis@home wrote:


"John Rumm" wrote in message
o.uk...

Some early implementations of RAID level 2 tried this. Bit level
splitting of data over some drives and applying FEC to generate check
and correct bits on parity drives.

Its not used these days since for obvious reasons - and it kind of
went against the whole raid philosophy in the first place, so calling
it "proper RAID" is a Dennis'ism really.

Show me where I called it a proper RAID?

Erm , how about a couple of posts back where you said "Ah well that was
probably in the days of proper RAIDs. The ones where it was done bitwise
across the disks and all the spindles and heads were synchronised.
They were expensive."

You are reading stuff that hasn't been written.

See above...

PS what do you think are the obvious reasons they died out?

"Died out" is perhaps over egging it - it never really got started. There
were several problems; Price was a significant factor in the first place -
it required bespoke drives

Well that's not exactly true, most of the drives at the time had sync
connectors and you just didn't use them if you didn't need them.

and controllers with non standard interfaces.

The interfaces were standards at the time there was nothing special about
the drives compared to other drives.

It also used a comparatively large number of drives compared to other RAID
setups as well, without providing the performance or redundancy advantages
either.

They were certainly redundant.
Performance relative to single drives was very quick.

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.


As a technology it was rendered obsolete almost immediately when the drive
manufacturers included at first equal (and shortly later, superior) FEC
within their drive firmware.

There was little or no firmware on drives at the time.
The integration of controllers did kill them off.
People like me were responsible as we decided to use SCSI and make the
controller designers do something more useful.
At the time every computer would have its own controller design, that was a
complete waste of time when there weren't enough engineers around to design
more useful bits like bit slice CPUs and bubble memory cards!

I actually went to a disk drive conference (I don't really know why) in the
early eighties, there were some real die hard engineers there that would
come along and sensing that I didn't design controllers start spewing
un-decipherable jargon. They looked a bit shocked when I said we were going
to use SCSI as you couldn't even buy a SCSI disk at the time. A year later
things were different.

That meant that a pair of mirrored drives on standard controllers offered
better reliability at a fraction of the cost. So game over for RAID 2.

I never saw a mirrored pair of drives at the time, it just wasn't going to
happen as you needed the parity bits to do correction and redundancy.

In article , Tinkerer invalidaddress@in
validaddress.invalid scribeth thus

"tony sayer" wrote in message
...
In article
s.com, Weatherlawyer scribeth thus
On Jun 22, 9:03 pm, tony sayer wrote:
Bought a new drive, Western digital IDE 250 GB back in March this year.

Bl^^dy thing has gone tits up already..

Most everything is backed up but there were a few things that were
forgotten about and now they are a lot more important;!.

There was a thread somewhere detailing some of the ways to recover data
apart from commercial outfits costing a lot of money. PC won't recognise
it apart from make and model number and thats as far as it goes..

Anyone any suggestions?..

Also anyone any suggestion as to a reliable make of drive as it seems to
me there're all getting rather bad!..

The police will supply any data they have about you but it incurs a
search fee. And a lot of moidering.

Don't believe all you read;!..


But how did they get involved with problems with your drive? Did
friends have an accident backing up?

Pardon?..


I think its a word play on PC.



Yes....


and silly ole me looking for the deeper meaning...
--
Tony Sayer

On Wed, 23 Jun 2010 22:58:01 +0100, Paul Bird wrote:
A low level reformat can sometimes help, but IME it usually only
delays the inevitable.

It won't actually write a "low level" format pattern to the drive, but
will serve to mark some sectors as "bad". However, it won't stop the
rot spreading.

. . . and the rot can spread remarkably quickly. Hours in my
experience.

Depends on the age of the drive, I've found. In the context of the OP,
correct - but it's not true of all drives, with older (ancient in
computing terms) often surviving for years with a few duff blocks.

(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? :-)

cheers

Jules

On 24/06/2010 15:20, Jules Richardson wrote:
On Wed, 23 Jun 2010 22:58:01 +0100, Paul Bird wrote:
A low level reformat can sometimes help, but IME it usually only
delays the inevitable.

It won't actually write a "low level" format pattern to the drive, but
will serve to mark some sectors as "bad". However, it won't stop the
rot spreading.

. . . and the rot can spread remarkably quickly. Hours in my
experience.

Depends on the age of the drive, I've found. In the context of the OP,
correct - but it's not true of all drives, with older (ancient in
computing terms) often surviving for years with a few duff blocks.

The one from the RAID* carried on for a month before I replaced it.
There were about three incidents of clumps of bad-block reports in that
time. As it was in a RAID anyway, so there was redundancy, I thought it
would be interesting to watch the rate of degradation; fuel for future
IT policies. The last clump of bad blocks was bigger than its
predecessors put together, which seemed like a good time to swap it.

Certainly not a case of a fatal failure within minutes or hours,
although Roland's right that it can sometimes go catastrophic a lot more
quickly.

Jon
(* Sorry to bang on about it -- it's the best example I have of a fully
instrumented drive failure; usually we just swap regardless, ASAP.)
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Jon Green wrote:
snip
Certainly not a case of a fatal failure within minutes or hours,
although Roland's right that it can sometimes go catastrophic a lot more
quickly.

Jon
(* Sorry to bang on about it -- it's the best example I have of a fully
instrumented drive failure; usually we just swap regardless, ASAP.)

You would *not* have wanted to be in charge of the radio station on a
cruise ship where one afternoon the ships comms started playing up, with
no new drives onboard, and I spent the evening starting to get a copy of
the data off onto another machine, begged the C/eng to get me a new
drive pronto (we were alongside) which he did thank heavens, got some
sleep, looked at it in the morning only to find it was worse, and got
enough off it restart the system when the new drive came onboard. My
experience is the quality of the equipment onboard is in inverse
proportion to the amount of money the pax are paying.

That's why I said when a drive starts to go, it can go in hours. Which
is not funny when it's not part of a RAID setup.

PB

"Huge" wrote in message
...
On 2010-06-24, John Rumm wrote:
On 24/06/2010 12:42, dennis@home wrote:

John, you're arguing with 'dennis the erroneous'. Why?

Because he likes to learn things, you can't learn things.

On 24/06/2010 16:27, Paul Bird wrote:
Jon Green wrote:
Certainly not a case of a fatal failure within minutes or hours,
although Roland's right that it can sometimes go catastrophic a lot
more quickly.

You would *not* have wanted to be in charge of the radio station on a
cruise ship where one afternoon the ships comms started playing up, with
no new drives onboard, and I spent the evening starting to get a copy of
the data off onto another machine, begged the C/eng to get me a new
drive pronto (we were alongside) which he did thank heavens, got some
sleep, looked at it in the morning only to find it was worse, and got
enough off it restart the system when the new drive came onboard.

You're right -- I wouldn't! I've done enough heroics in my time to want
to prevent rather than cure where possible.

My
experience is the quality of the equipment onboard is in inverse
proportion to the amount of money the pax are paying.

I'm not greatly surprised, TBH. The bigger the money, the more
boneheaded number-crunchers you'll find getting in the way of common
sense, each eager to demonstrate that they've justified their salary by
achieving cuts in "unnecessary overheads". Like, just for instance,
eliminating enough shelf stock that a ship days from port can no longer
remain self-sufficient. I've been in analogous situations, and I know
your pain!

That's why I said when a drive starts to go, it can go in hours. Which
is not funny when it's not part of a RAID setup.

Oh, quite. Any mission-critical kit should have fallbacks planned and
implemented as part of its specification. Even something as banal as
the shipboard radio station is something the pax will notice missing.
If you have to cite "technical problems" as the reason, your bejewelled
and fur-wrapped customers will be wondering what else is badly
maintained. How about the bridge equipment? The escape davits?

Tar, ship, caulking for the use of, ha'p'orth thereof.

Jon
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On 24/06/2010 16:45, dennis@home wrote:

"Huge" wrote in message
...
John, you're arguing with 'dennis the erroneous'. Why?

Because he likes to learn things, you can't learn things.

Word to the wise: that's because Huge knows enough things already that
little's new any more.

Jon
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dennis@home wrote:


"David WE Roberts" wrote in message
...


Redundant Array of Inexpensive Discs was impressive in a production
environment, apart from the fact that the discs were anything but
inexpensive.

Ah well that was probably in the days of proper RAIDs.
The ones where it was done bitwise across the disks and all the spindles
and heads were synchronised.
They were expensive.



Bwahahaha.

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 and drives
that were 10MB per platter.
--
Roland Perry

"John Rumm" wrote in message
o.uk...

When I started they were in the 5 MB range and were 14" dia, you built
controllers with RLL compression and stuff like that.
Typically they would occupy a couple of MB1 sized cards or a bit more.

You probably did not have one of those on your home computer though...

I didn't have a home computer for ages, never really saw the attraction.
By the time I got one 50MB hard disks were common.

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 and drives
that were 10MB per platter.

So it's not just me then? (looks at ST506 he keeps to frighten the
children)

Andy

"Huge" wrote in message
...
On 2010-06-24, Andy Champ wrote:
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 and drives
that were 10MB per platter.

So it's not just me then?

Hell, no.

I still have some 5 track paper tape ...


I have an 8-track player.

"Tim Streater" wrote in message
...

Ah, now that's going back a bit. I haven't seen that since I worked on an
Elliott 803.

World's best tape readers ... 1,000 cps and could stop between two
characters, quite often without even tearing the tape.

--
Tim Ward - posting as an individual unless otherwise clear
Brett Ward Limited - www.brettward.co.uk
Cambridge Accommodation Notice Board - www.brettward.co.uk/canb
Cambridge City Councillor

"Huge" wrote in message
...
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 ...


Ah, the Good Old Days.

My first machine had a 350M HDD, and I paid over two thousand dollars (USD)
for it. I bought the upgrade graphics/game card that allowed a joystick so I
could play Flight Simulator. It was a bit jerky as the scenery files
changed.

I recently bought a 500G external HDD for $60. I have several Thumb
Drives -- flash drives in some circles -- with more capacity than my first
computer. I bought a 128M flash drive when they first came out for something
like $15, now they give away drives with 8 times that capacity for free to
the first 50 shoppers on Saturday.

It sucks to be a trail blazer. I buy stuff that leads the industry, and it's
obsolete by the end of the month. I bought a flat screen TV a year ago, and
when the store was out of stock on my TV, the next shipment was better and
cheaper and mine was discontinued.

On Thu, 24 Jun 2010 22:18:51 +0100, Tim Ward wrote:

"Tim Streater" wrote in message
...

Ah, now that's going back a bit. I haven't seen that since I worked on
an Elliott 803.

World's best tape readers ... 1,000 cps and could stop between two
characters, quite often without even tearing the tape.

Yes, I remember ours. There's a working one at Bletchley Park.



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

*lightning protection* - a w_tom conductor

On Thu, 24 Jun 2010 21:00:52 +0000, Huge wrote:

On 2010-06-24, Andy Champ wrote:
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 and
drives that were 10MB per platter.

So it's not just me then?

Hell, no.

I still have some 5 track paper tape ...

I used to have to USE 5 track paper tape.



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

*lightning protection* - a w_tom conductor

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 were initially 2MB, latre upgrade to
4MB. Alan Ibbetson and I hand punched a paper tape to patch the operating
system...

Think they were four platters, so 0.66MB per platter...



--
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dennis@home wrote:

When I started they were in the 5 MB range and were 14" dia, you built
controllers with RLL compression and stuff like that.
Typically they would occupy a couple of MB1 sized cards or a bit more.


RLL Compression? Pray tell me more.

Andy

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

On Thu, 24 Jun 2010 22:50:20 +0100, Tim Streater wrote:

In article ,
Bob Eager wrote:

On Thu, 24 Jun 2010 22:18:51 +0100, Tim Ward wrote:

"Tim Streater" wrote in message
...

Ah, now that's going back a bit. I haven't seen that since I worked
on an Elliott 803.

World's best tape readers ... 1,000 cps and could stop between two
characters, quite often without even tearing the tape.

Yes, I remember ours. There's a working one at Bletchley Park.

I must see that next time I'm there.

It's on the 803, strangely enough!

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

*lightning protection* - a w_tom conductor

On Thu, 24 Jun 2010 22:41:40 +0100, Andy Champ wrote:

dennis@home wrote:

When I started they were in the 5 MB range and were 14" dia, you built
controllers with RLL compression and stuff like that. Typically they
would occupy a couple of MB1 sized cards or a bit more.


RLL Compression? Pray tell me more.

Indeed. Which reminds me...I have two single-platter 10MB drives in my
workshop that I need to get going - DEC RL02s...




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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 and drives
that were 10MB per platter.

Just shows how little you ever really knew about anything.

"Andy Champ" wrote in message
. uk...
dennis@home wrote:

When I started they were in the 5 MB range and were 14" dia, you built
controllers with RLL compression and stuff like that.
Typically they would occupy a couple of MB1 sized cards or a bit more.


RLL Compression? Pray tell me more.

Well you replace long streams of the same bits with shorter ones.
But as you mention it I doubt if thats why RLL coding was used.

Jeff Strickland wrote:
"Huge" wrote in message
...
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 ...


Ah, the Good Old Days.

My first machine had a 350M HDD, and I paid over two thousand dollars (USD)
for it. I bought the upgrade graphics/game card that allowed a joystick so I
could play Flight Simulator. It was a bit jerky as the scenery files
changed.

My first machine had a tape drive, the twin 5 1/14" floppy disks were extra.

"The Natural Philosopher" wrote in message
...
Jeff Strickland wrote:
"Huge" wrote in message
...
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 ...


Ah, the Good Old Days.

My first machine had a 350M HDD, and I paid over two thousand dollars
(USD) for it. I bought the upgrade graphics/game card that allowed a
joystick so I could play Flight Simulator. It was a bit jerky as the
scenery files changed.

My first machine had a tape drive, the twin 5 1/14" floppy disks were
extra.



I once borrowed an Apple IIC to play Leisure Suit Larry. It had a pair of
5.25 drives. I managed to work through it and find all of the treasures. Now
THAT was a game ...

On 24/06/2010 18:42, 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 and drives
that were 10MB per platter.

Strange. I go back as far, and I definitely do remember drives that
went flaky when you changed them between vertically and horizontally
mounted. And the best solution, as Jules said, was to pull off all the
data, reformat, and restore. Didn't happen all the time by any means,
but I'd certainly seen it occur.

Jon
--
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with 'green-lines'.
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Website: http://www.green-lines.com/

"Jon Green" wrote in message
o.uk...
On 24/06/2010 18:42, 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 and drives
that were 10MB per platter.

Strange. I go back as far, and I definitely do remember drives that went
flaky when you changed them between vertically and horizontally mounted.
And the best solution, as Jules said, was to pull off all the data,
reformat, and restore. Didn't happen all the time by any means, but I'd
certainly seen it occur.


I remember drives that were sensitve to changes in orientation. My DVR
claims to be sensitve to changes in orientation. My cable provider says the
DVR won't work right if it's not laying flat. My last DVR had a sticker on
it warning me that it absolutely must not be tilted or tipped -- the
difference is lost on me, but the sticker was there.

I remember that the HDD had to be set in the orientation it was to be used
in, then formatted or the formatting would not work.

On 24/06/2010 23:36, Jeff Strickland wrote:

I remember drives that were sensitve to changes in orientation. My DVR
claims to be sensitve to changes in orientation. My cable provider says the
DVR won't work right if it's not laying flat. My last DVR had a sticker on
it warning me that it absolutely must not be tilted or tipped -- the
difference is lost on me, but the sticker was there.

I bet I know why, and the reason (in this case) is not to do with the
disk. That's a piece of living room media equipment, and the watchword
is "quiet".

Chances are, the case was designed to convect as much heat as possible
before fan assistance, so that the fan can be either smaller and
quieter, or omitted completely. But the case design was predicated on
being horizontal, and the airflows with it vertical wouldn't purge
enough heat in time.

Not that I've played that game myself, not at all...

Jon
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In message , at 21:00:23 on Thu, 24 Jun
2010, Huge remarked:
No, I don't remember that, and I go back all the way to 1980

Pah. Newbie.

There weren't many hard drives of the sort the public might buy, before
then. If Jules was referring to ones you'd only find in a computer room,
it wasn't an especially helpful remark to make to an end user.

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.

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

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).

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

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.
--
Roland Perry

In message , at 14:24:57 on
Thu, 24 Jun 2010, Jeff Strickland remarked:
I recently bought a 500G external HDD for $60. I have several Thumb
Drives -- flash drives in some circles -- with more capacity than my first
computer.

The first computer I owned - bought new and belonging entirely to me -
in about 1975, was shipped as standard with 128bytes of memory (a 1kbit
chip arranged 128x8). But I splashed out and bought two more, so I had
384bytes to play with.
--
Roland Perry

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).
--
Roland Perry

In message , at
23:48:40 on Thu, 24 Jun 2010, John Rumm
remarked:
RLL Compression? Pray tell me more.

Run length limiting. Using a RLL controller gained an extra 50%
capacity, but at the expense of a reduced signal to noise and grater
risk of unrecoverable read error.

Other way round, surely? It was a coding method to make sure you never
had too many of the same polarity bits "in a row", which risks
unreadability. What makes a magnetic storage medium work is *changes* in
polarity.
--
Roland Perry

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.

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!

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"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.