18 Mar
2005
18 Mar
'05
2:39 a.m.
willisjo at zianet.com wrote:
However, I am a tad concerned about what will happen
to our prized hobby when such items as 9-track tapes,
TK50s, and TU58 DECtape-IIs truly become absolute
unobtainium.
As I have stated many times before, I believe the solution is for us to
open our own factories to make them.
MS
19 Mar
19 Mar
4:28 p.m.
On Fri, 18 Mar 05 07:39:43 GMT
msokolov at ivan.Harhan.ORG (Michael Sokolov) wrote:
willisjo at zianet.com wrote:
I suspect, rather than 'factories', that it would be similar to being a
'gunsmith.' There are plenty of artisan machinists who make all sorts
of complex machinery. There's an active hobby of making hobby steam and
gasoline engines, for instance.
It's a role for craftsmen, not industrial workers. (Industrial workers
by design know little about what they're doing).
However, I am a tad concerned about what will
happen
to our prized hobby when such items as 9-track tapes,
TK50s, and TU58 DECtape-IIs truly become absolute
unobtainium.
As I have stated many times before, I believe the solution is for us
to open our own factories to make them.
MS 
4:36 p.m.
New subject: other hobbies
Scott Stevens wrote:
I suspect, rather than 'factories', that it
would be similar to being a
'gunsmith.' There are plenty of artisan machinists who make all sorts
of complex machinery. There's an active hobby of making hobby steam and
gasoline engines, for instance.
I've heard of steam not gasoline engines as a hobby.Now when was the
last time you
heard of anybody building say a "horse-less wagon" for moving your
"steam powered
Analytical engine" around the country.
It's a role for craftsmen, not industrial workers.
(Industrial workers
by design know little about what they're doing).
But back to magnetic tape, don't think you can re-create that with out
alot of machinery.
The big problem is often the chemical process on the plasic or
binder/magnetic stuff
is trade secrets.
20 Mar
20 Mar
2:45 a.m.
New subject: other hobbies
woodelf wrote:
But back to magnetic tape, don't think you can
re-create that with out
alot of machinery.
The big problem is often the chemical process on the plasic or
binder/magnetic stuff
is trade secrets.
Surely you could use cheap commodity tape, like VHS video tape?
Obviously this woul only work for machines that use up to 1/2" tape.
Gordon.
1:02 p.m.
New subject: other hobbies
Gordon JC Pearce wrote:
Surely you could use cheap commodity tape, like VHS video tape?
Obviously this woul only work for machines that use up to 1/2" tape.
Cleap tape DON'T work. Now how long do you expect VHS to last
with DVD players $50?
Gordon.
Ben alias woodelf
1:38 p.m.
New subject: other hobbies
woodelf wrote:
My worry would be that the coercivity is almost certain to be wrong. I
can rememeber when fooling around with reel-to-reel video recorders that
if you used 'high band' tape on a 'low band' machine you got almost no
signal off the tape.
I have also been told that 1/2" computer tape makes lousy video tape (by
somebody who tried it in an N1500), I suspect the reverse is also true.
And anyway, how much longer do you expect to find VHS tapes on sale just
anywhere?
But back to magnetic tape, don't think you
can re-create that with out
alot of machinery.
The big problem is often the chemical process on the plasic or
binder/magnetic stuff
is trade secrets.
Surely you could use cheap commodity tape, like VHS video tape? Obviously this woul only work for machines that use up
to 1/2" tape.
As regards slittling the tape, classic camera enthusiasts (another of
_my_ hobbies) routinely slit film down to make it fit obscure cameras
(e.g. turn 120 into 127). This is in one respect easier than tape (film
is thicker and stiffer), in aother respect harder (you have to do it in
total darkness). Tyipcally, you make up a jig to hold a couple of razor
blades the right distance apart, and run the film over them -- often
using a 'junk' camera, like a Box-Brownie (for 120 or 620 input), some
35mm compact (for 35mm input, to make subminature film), etc. Doubtless a
similar idea could be made for magnetic tape.
-tony
2:34 a.m.
On Sat, 19 Mar 2005 16:28:45 -0500, Scott Stevens <chenmel at earthlink.net> wrote:
On Fri, 18 Mar 05 07:39:43 GMT
msokolov at ivan.Harhan.ORG (Michael Sokolov) wrote:
Hmm... Drivesmith... one problem, of course, is that the tolerances
for hard drives are somewhat tighter than for strictly mechanical
devices such as steam engines and guns. I know people who make both
(steam and guns), but I would seriously hesitate to make any sort of
drive bits newer than, say, an RK05.
Having said that, someday I know I'll have to face at least one round
of this... I have several DF32 drives that I expect have seriously
worn plating (I've only ever tested the electronics, but I _have_ spun
the platters up and down, 20 years ago, long before I knew it could
cause a problem). Getting a replacement platter fashioned and turned
to suitable smoothness is completely within the realm of accessible
tools for steam engines, etc. It's really no worse than turning a
brake rotor. My only real concern is _plating_ the platter. Setting
up an electroplating rig is easy enough (I copper plated a number of
nickels and quarters as a lad ;-) presuming one can a) come up with an
acceptable formula for the coating, and b) gain access to the various
soluable compounds to mix up a batch of plating solution. Even when
that's done, one still has to construct the timing track generator,
but at least that's well documented, so one could build the real deal
As I have stated many times before, I believe the
solution is for us
to open our own factories to make them.
I suspect, rather than 'factories', that it would be similar to being a
'gunsmith.' There are plenty of artisan machinists who make all sorts
of complex machinery. from old DEC bits, or one could simulate a formatter
with modern
circuitry... the timing pulses are not that bad.
Vince and I have also kicked around what it would take to build a
modern solid-state replacement for just the rotating media (there's
already a prototype 74LS replacement for the entire 4-drive
assembly)... it's honestly easier to replicate the entire drive
assembly (since that can be done with 100% digital circuits), but the
whole point would be to have a modern replacement _just_ for the
platter and possibly the heads.
Extending the need for a drivesmith to eventually encompass
replacements for, say, 200GB rotating media is left as an exercise for
the reader. :-)
-ethan
2:54 a.m.
Ethan Dicks wrote:
Having said that, someday I know I'll have to face
at least one round
of this... I have several DF32 drives that I expect have seriously
worn plating (I've only ever tested the electronics, but I _have_ spun
the platters up and down, 20 years ago, long before I knew it could
cause a problem). Getting a replacement platter fashioned and turned
What about RL02s? Are they meant to be left alone once mounted and run
up, or can you treat them like big Zip disks?
to suitable smoothness is completely within the realm
of accessible
tools for steam engines, etc. It's really no worse than turning a
brake rotor. My only real concern is _plating_ the platter. Setting
Turning brake discs is something I've never understood. They're cheap.
They're your *brakes*. If the disc is scored or corroded, *throw the
pair away*. For the amount of hassle that's involved, it's just not
worth doing it twice. </offtopic>
up an electroplating rig is easy enough (I copper
plated a number of
nickels and quarters as a lad ;-) presuming one can a) come up with an
acceptable formula for the coating, and b) gain access to the various
I thought the coating was sprayed on? Looking at the edge of an RL02,
there are clear "dribble marks" where it's run down the side of the disk.
soluable compounds to mix up a batch of plating
solution. Even when
that's done, one still has to construct the timing track generator,
but at least that's well documented, so one could build the real deal
from old DEC bits, or one could simulate a formatter with modern
circuitry... the timing pulses are not that bad.
I did wonder about such a thing. I'm still trying to get my head round
the DF32 timing for my PDP8 emulator.
Gordon.
4:47 a.m.
What about RL02s? Are they meant to be left alone
once mounted and run
up, or can you treat them like big Zip disks?
Try to make adapter to convert from one interface to IDE interface
and use CF card. Smallest is 8MB all the way to 8GB and price is
good on 1GB and below. If one knows well with SD stuff, great!
Turning brake discs is something I've never
understood. They're cheap.
They're your *brakes*. If the disc is scored or corroded, *throw the
pair away*. For the amount of hassle that's involved, it's just not
worth doing it twice. </offtopic>
Agreed.
up an
electroplating rig is easy enough (I copper plated a number of
nickels and quarters as a lad ;-) presuming one can a) come up with an
acceptable formula for the coating, and b) gain access to the various
I thought the coating was sprayed on? Looking at the edge of an RL02,
there are clear "dribble marks" where it's run down the side of the disk.
Gordon.
12:51 p.m.
On Sun, 20 Mar 2005 09:47:36 +0000, jpero at sympatico.ca
<jpero at sympatico.ca> wrote:
Try to make adapter to convert from one interface to
IDE interface
and use CF card. Smallest is 8MB all the way to 8GB and price is
good on 1GB and below. If one knows well with SD stuff, great!
Flash isn't a perfect replacement for rotating magnetic media for any
OS that has a swap partition... heavy use will begin to deplete
regions of the Flash media. Before anyone says that it will take "X
million years..." I want to comment that I've seen it happen myself in
heavy use situations... specifically, I rigged up an old Olympus
camera as a webcam for my "EarthDial". I used this camera because it
was the end of summer at the South Pole and there wasn't time to get
get something more suitable before our 8 month winter started. The
camera was controllable via RS-232 serial line and gphoto. The one
weakness was its 8MB SmartMedia storage. I took several thousand
pictures, one every 5 minutes for several weeks. As the weeks wore
on, the capacity of the card diminished by about 5%.
Also... I happen to have a small stack of 4MB CF cards. I've never
seen any with lower capacity than that (in full-sized PCMCIA
form-factor, I happen to have 2.5MB cards, and ISTR there were 1MB
cards).
The low end doesn't matter for a theoretical RL02 replacement... those are 10MB.
In the case of the DF32, we've looked at battery-backed SRAM, not CF.
The one end-to-end (not platter-only) replacement project uses a
40-pin potted SRAM/battery combo like the clock/SRAMs in a
SPARCstation, but much larger. With RAM sizes, etc, it's not absurd
to consider SRAM for an RK05 or RL01, but by the time you get to RL02
sizes, board size and component expenses start to climb.
Platters are very hard high quality aluminum alloys...
Nice description of modern platters... I knew some of that stuff, but
not the details. Certainly relevant to the issue of someday folks
like us having to manufacture replacements. Unfortunately, not as
relevant to the more immediate requirement to make or re-make DF32
platters, which are not like aluminum/glass platters.
-ethan
3:08 p.m.
Ethan wrote:
Flash isn't a perfect replacement for rotating
magnetic media for any
OS that has a swap partition... heavy use will begin to deplete
regions of the Flash media. Before anyone says that it will take "X
million years..."
Not millions of years, but more than a few.
I want to comment that I've seen it happen myself
in
heavy use situations... specifically, I rigged up an old Olympus
camera as a webcam for my "EarthDial". I used this camera because it
was the end of summer at the South Pole and there wasn't time to get
get something more suitable before our 8 month winter started. The
camera was controllable via RS-232 serial line and gphoto. The one
weakness was its 8MB SmartMedia storage. I took several thousand
pictures, one every 5 minutes for several weeks. As the weeks wore
on, the capacity of the card diminished by about 5%.
That's because "SmartMedia" is a horrible misnomer. It really should
be called "DumbMedia", because there's no intelligence in the card
at all. So it does no wear levelling.
CF and SD cards have a built-in intelligent controller that performs
wear levelling automatically. Some (or all?) cards also have automatic
replacement of bad blocks with spares. They will last much longer than
SmartMedia in an environment that rewrites certain blocks frequently,
such as swap space. They'll still eventually were out, of course, but
it will take quite a while.
The exact details of the wear-levelling and bad block replacement
are unspecified by the CF and SD standards. Similarly to the SCSI
and ATA standards, CF and SD just present a logical array of good
blocks, with the geometry details hidden. Different manufacturers
may have different algorithms. Sandisk has a white paper describing
theirs in general terms.
If I were buying a card for a high-wear application, I'd want to buy a
well-known reputable brand such as Sandisk or Lexar, rather than the
cheapest off-brand card at Frys.
Eric
3:15 p.m.
New subject: Flash longevity
It was written....
They'll still eventually were out, of course, but
it will take quite a while.
... snip ..
If I were buying a card for a high-wear application, I'd want to buy a
well-known reputable brand such as Sandisk or Lexar, rather than the
cheapest off-brand card at Frys.
Uh... no. Set up a swap partition on a lexar flash drive. You won't get more
than a month of use at best. I've done it. Twice.
Jay
3:29 p.m.
New subject: Flash longevity
From: "Jay West" <jwest at classiccmp.org>
Sent: Sunday, March 20, 2005 2:15 PM
It was written....
Flash drives have a large but limited number of erases. They make great
solid state drives but not for swap devices. For a classic system needing a
small number of mb of swap space RAM is the best answer.
Randy
www.s100-manuals.com
They'll still eventually were out, of course,
but
it will take quite a while.
... snip ..
If I were buying a card for a high-wear application, I'd want to buy a
well-known reputable brand such as Sandisk or Lexar, rather than the
cheapest off-brand card at Frys.
Uh... no. Set up a swap partition on a lexar flash drive. You won't get
more than a month of use at best. I've done it. Twice.
Jay
3:44 p.m.
New subject: Flash longevity
It was written...
Flash drives have a large but limited number of
erases. They make great
solid state drives but not for swap devices. For a classic system needing
a small number of mb of swap space RAM is the best answer.
Ugggg... sorry. It wasn't a swap partition I created in flash. It was an OS
install partition (to install the OS FROM, not to). I was learning the
intricacies of "label & newfs" at the time, and had quite a few attempts in
a short interval but the lexar drive died. This happened again to a second
one in short order.
So the "writing" I was doing was formatting and loading, not general use. It
didn't hold up well in this application at all. Based on my own experience,
I would only use flash for emergency storage, not for something I planned to
read a bunch - let alone write. Using it as a daily backup regimin wouldn't
be good either.
Then again, maybe I just had two bad devices in a row.
Jay
4 p.m.
New subject: Flash longevity
Jay wrote:
It wasn't a swap partition I created in flash. It
was an OS
install partition (to install the OS FROM, not to). I was learning the
intricacies of "label & newfs" at the time, and had quite a few attempts
in a short interval but the lexar drive died. This happened again to a
second one in short order.
Strange. I've done a lot of that sort of thing on Sandisk CF and SD
cards with no trouble. And I have used a 2GB Sandisk CF as a swap
partition on a laptop for more than nine months with no observed ill
effects.
Then again, maybe I just had two bad devices in a row.
Possible, but seems unlikely. I'm not sure how else to explain it
though. Overwriting an entire partition in a CF multiple times to
do installations *from* shouldn't cause any significant wear.
Eric
4:51 p.m.
New subject: Flash longevity
From: "Eric Smith" <eric at brouhaha.com>
Sent: Sunday, March 20, 2005 3:00 PM
Jay wrote:
To my knowledge (which may be wrong) is that the reads are unlimited, it is
the erasing that causes problems.
Using the drive as a worm device should be perfect for it.
CF cards are 5v tolerant devices and may be sensitive to over-voltage, if
you are running it at 5v a current limiting resistor might be a good idea.
Randy
www.s100-manuals.com
It wasn't a swap partition I created in
flash. It was an OS
install partition (to install the OS FROM, not to). I was learning the
intricacies of "label & newfs" at the time, and had quite a few attempts
in a short interval but the lexar drive died. This happened again to a
second one in short order.
Strange. I've done a lot of that sort of thing on Sandisk CF and SD
cards with no trouble. And I have used a 2GB Sandisk CF as a swap
partition on a laptop for more than nine months with no observed ill
effects.
Then again, maybe I just had two bad devices in a
row.
Possible, but seems unlikely. I'm not sure how else to explain it
though. Overwriting an entire partition in a CF multiple times to
do installations *from* shouldn't cause any significant wear.
Eric
12:03 p.m.
New subject: Flash longevity
Eric
To my knowledge (which may be wrong) is that the reads are unlimited, it is
the erasing that causes problems.
Using the drive as a worm device should be perfect for it.
CF cards are 5v tolerant devices and may be sensitive to over-voltage, if
you are running it at 5v a current limiting resistor might be a good idea.
Randy
www.s100-manuals.com
21 Mar
21 Mar
8:53 a.m.
On Sun, 20 Mar 2005 12:51:13 -0500
Ethan Dicks <ethan.dicks at gmail.com> wrote:
On Sun, 20 Mar 2005 09:47:36 +0000, jpero at
sympatico.ca
<jpero at sympatico.ca> wrote:
Well, depending on the age of the hardware, it might be best to just
replace the 'swap' partition/area of the hard drive being emulated with
modern, cheap DRAM memory. The swap area doesn't have to be
non-volatile, after all.
This depends, of course, on it being possible to specify where swap is
located, and not to just blindly use a flash drive as a plug-in HD
replacement.
-Scott
Try to make adapter to convert from one interface
to IDE interface
and use CF card. Smallest is 8MB all the way to 8GB and price is
good on 1GB and below. If one knows well with SD stuff, great!
Flash isn't a perfect replacement for rotating magnetic media for any
OS that has a swap partition... 
10:42 a.m.
On Mon, 21 Mar 2005 14:53:03 +0100, Scott Stevens <chenmel at earthlink.net>
wrote:
On Sun, 20 Mar 2005 12:51:13 -0500
Ethan Dicks <ethan.dicks at gmail.com> wrote:
The best practice is to not use swap if you use a flashdrive.
Even the newest flash generation will fail early if it gets written to too
often.
Each block of NAND flash can be rewritten up to a million times.
This may seem to be a lot until you start doing your figures.
It is the most frequently changed block that will cause the drive to fail,
and that will be in the file system structures.
Even with the best case scenario, the drive will wear out within two years.
--
Bj?rn
On Sun, 20 Mar 2005 09:47:36 +0000, jpero at
sympatico.ca
<jpero at sympatico.ca> wrote:
Well, depending on the age of the hardware, it might be best to just
replace the 'swap' partition/area of the hard drive being emulated with
modern, cheap DRAM memory. The swap area doesn't have to be
non-volatile, after all.
This depends, of course, on it being possible to specify where swap is
located, and not to just blindly use a flash drive as a plug-in HD
replacement.
Try to make adapter to convert from one interface
to IDE interface
and use CF card. Smallest is 8MB all the way to 8GB and price is
good on 1GB and below. If one knows well with SD stuff, great!
Flash isn't a perfect replacement for rotating magnetic media for any
OS that has a swap partition...
12:20 p.m.
Scott Stevens wrote:
Well, depending on the age of the hardware, it might be
best to just
replace the 'swap' partition/area of the hard drive being emulated with
modern, cheap DRAM memory. The swap area doesn't have to be
non-volatile, after all.
Why not just get more ram and forget swap space. :)
I think swap space needs to be non volitile on the system, the PDP/8
comes to mind where you have to swap memory around. Also some
operations may need to be continued after a power falure rather than
restarted like calculating PI to xxx decimal places.
This depends, of course, on it being possible to
specify where swap is
located, and not to just blindly use a flash drive as a plug-in HD
replacement.
Ben alias woodelf
20 Mar
20 Mar
12:01 p.m.
On Sun, 20 Mar 2005 07:54:06 +0000, Gordon JC Pearce <gordon at gjcp.net> wrote:
Ethan Dicks wrote:
RL02s are frequently mounted/dismounted, changed, etc. It's somewhat
common on a stable system to leave the system pack mounted, but
changing data packs is quite ordinary. The heads never rest on the
platters, so there's no question of wearing off the oxide. When it
_does_ happen, it's a head crash.
... I have several DF32 drives that I expect have
seriously worn plating...
What about RL02s? Are they meant to be left alone once mounted and run
up, or can you treat them like big Zip disks? I thought the coating was sprayed on? Looking at the
edge of an RL02,
there are clear "dribble marks" where it's run down the side of the disk.
An RL02 platter is a modern-style oxide-and-binder-coated thin
aluminum platter. A DF32 disk is a nearly 1cm-thick hunk of steel
with a chrome-like plating. One problem with the DF32 is that
repeated spin up/spin-down cycles wear through the plating.
-ethan
1:32 p.m.
On Sat, 19 Mar 2005 16:28:45 -0500, Scott Stevens <chenmel at earthlink.net>
wrote:
Agereed. I think that _most_ mechanical parts for classic computers could
be made ina good home workshop, with the exception of disk/tape heads,
and probably bits for inside HDAs. That still leaves a lot that could be
made.
I certainly think that any part for, say, an ASR33 could be made at home.
It may not least as long as the original, but do you really need to run
the machine 24/7? :-)
Which, alas, leaves storage devices as the main problem. Apart from
heads, I think parts for floppy drives could be made at home. Hard drives
are a lot worse. Even things like the spindle for an RK05 would be a
serious project (does that one have a ferrofluid seal in it? Some drives
certainly do).
On Fri, 18 Mar 05 07:39:43 GMT
msokolov at ivan.Harhan.ORG (Michael Sokolov) wrote:
Hmm... Drivesmith... one problem, of course, is that the tolerances
for hard drives are somewhat tighter than for strictly mechanical
devices such as steam engines and guns. I know people who make both
(steam and guns), but I would seriously hesitate to make any sort of
drive bits newer than, say, an RK05. As I have stated many times before, I believe the
solution is for us
to open our own factories to make them.
I suspect, rather than 'factories', that it would be similar to being a
'gunsmith.' There are plenty of artisan machinists who make all sorts
of complex machinery.
Having said that, someday I know I'll have to face at least one round
of this... I have several DF32 drives that I expect have seriously
worn plating (I've only ever tested the electronics, but I _have_ spun
the platters up and down, 20 years ago, long before I knew it could
cause a problem). Getting a replacement platter fashioned and turned
to suitable smoothness is completely within the realm of accessible
tools for steam engines, etc. It's really no worse than turning a
brake rotor. My only real concern is _plating_ the platter. Setting
Sure. I suspect you could skim the surface of the existing platter rather
than start from new (I can't believe the thickness is very critical). Of
course you would have to replate it.
up an electroplating rig is easy enough (I copper
plated a number of
nickels and quarters as a lad ;-) presuming one can a) come up with an
acceptable formula for the coating, and b) gain access to the various
I thought it was mostly nickel, but I am not sure.
soluable compounds to mix up a batch of plating
solution. Even when
Indeed. I know the gold plating is not something to try at home... (the
only reasonable method uses gold cyanide..). If you could find out what
metal(s) the plating consisted of, you could probably find details of the
chemicals to use in some of the old books on workshop methods or
electrical engineering that Lindsay have reprinted. I am pretty sure I've
got this info somewhere.
that's done, one still has to construct the timing
track generator,
but at least that's well documented, so one could build the real deal
from old DEC bits, or one could simulate a formatter with modern
circuitry... the timing pulses are not that bad.
Vince and I have also kicked around what it would take to build a
modern solid-state replacement for just the rotating media (there's
already a prototype 74LS replacement for the entire 4-drive
assembly)... it's honestly easier to replicate the entire drive
assembly (since that can be done with 100% digital circuits), but the
whole point would be to have a modern replacement _just_ for the
platter and possibly the heads.
And it would probably be even eaiser to get the whole machine, storage
and all, into a couple of FPGAs, or as a software emulator...
I guess I am odd, but I feel that the peripherals are as much a part of
classic computing as the CPU. Sure it can be fun to design new
peripherals for the classics, to link CF cards to a PDP8 or whatever.
It's also good to keep the origianl peripherals running.
-tony
7058
days inactive
7061
days old
21 comments
11 participants
participants (11)
-
ard＠p850ug1.demon.co.uk -
bfranchuk＠jetnet.ab.ca -
bv＠norbionics.com -
cctalk＠randy482.com -
chenmel＠earthlink.net -
eric＠brouhaha.com -
ethan.dicks＠gmail.com -
gordon＠gjcp.net -
jpero＠sympatico.ca -
jwest＠classiccmp.org -
msokolov＠ivan.Harhan.ORG