Does anyone know what are the magnetic strength of the
different media inside DLT type tapes? I am trying to
understand what are the differences between a
CompacTape
CompacTape II
CompacTape III also know as a DLT tape
I can see any physical difference except for the
color of the name. I assume that the tape media
have different magnetic strengths.
There was a recent discussion about the magnetic
strength of 5 1/4" floppies - I remember that the
DSDD were 300 o and the HD were 600 o.
Do the different CompacTape media
have the same sort of differences. I did look up
the quantum.com web site and it seems to state
that the CompacTape III are metal tapes.
Sincerely yours,
Jerome Fine
Anybody out there within a reasonable driving distance (6 hours?) of
Austin, Texas that has any old DEC gear they'd like to get rid of to
a good home? I've got a two-car garage thats finished out with carpet
and paneling, and I'd like to start that collection of DEC stuff I
always wanted. I'm looking for VT1xx/2xx/3xx terminals, MicroVAX/
VAX equipment, PDP-11 (especially) gear, etc.
Stuff I've got for sale or trade or donation if you need it bad enough:
Six 1200 watter power supplies for a Sun 4/690MP
Six 2.1gig SCSI differential FH 5.25" HDs from a 4/690MP
Six 1.3gig IPI 5.25" FH HDs from a 4/690MP
16-slot VME cardcage/backplane/blower assembly from a
Sun 4/690MP
Five 4/330 / 4/630MP deskside VME chassis
One SCSI drive shelf and two IPI drive shelves/trays (with
slide rails) for a 19" rack
Two IBM POWERServer 530 RS/6000 servers, each with 64mb RAM,
2.3gig Exabyte tape drives, one with CD-ROM and 1gig
HD, both with IBM 3151 amber terminals. AIX 4.1.3
loaded, with AIX on CD-ROM included. Other stuff
like a 16-port serial breakout box, etc.
Couple of Toshiba laptops with the orange plasma screen (not
sure about the models, I think one's a 3100 and one
a 5100; I used them for serial terminals)
If anybody's interested in any of this equipment, please let me know.
I'd love to see it go to a good home where someone cna get some use
out of it, and possibly get something for me to play with in return.
Bill
--
Bill Bradford * mrbill(a)mrbill.net / http://www.mrbill.net
mrbill(a)sunhelp.org / http://www.sunhelp.org
---------------------------------------------------------------------
"Never criticize anybody until you have walked a mile in their shoes,
because by that time you will be a mile away and have their shoes."
-- Unknown
At 10:08 PM 10/25/99 -0700, you wrote:
>>Two 1MHz busses will be faster than a single 2MHz bus if they are being used
>>for different purposes, such as one for I/O and one for memory accesses.
>
>But my point is that one 4 MHz synchronous bus is going to be faster than
>two 1 MHz busses in all cases.
No, no and no. A dumb 4Mhz burst bus that requires cpu attention to work
will be many times slower in actual applications than two 1Mhz buses with
distributed arbitration and such smarts. That's all the point of the
discussion. That's why raw numbers tend to be meaningless. That's why
system designers nowadays make decisions based on simulations and not
on raw specs.
Carlos.
In a message dated 10/31/99 9:19:47 PM Eastern Standard Time,
mikeford(a)socal.rr.com writes:
>
> Heresy beyond heresy I would actually like to see people with eprom burners
> be able to make a few bucks by burning the eproms. I think it would make a
> DANDY little web business. Now obviously the database and the burning
> businesses need to be completely separate, people would be all over us if
> we "sold" burnt eproms, but what would be wrong with burning customer
> supplied data and printing a label with supplied text?
i could burn/read eproms with my BAL500 card that's in my apple ][+ if
someone can tell me how to use it...
DB Young Team OS/2
--> this message printed on recycled disk space
view the computers of yesteryear at
http://members.aol.com/suprdave/classiccmp/museum.htm
(now accepting donations!)
The reality of this quandary is that the answer lies not in the legality of
copying the EPROMs, but in the likelihood of getting caught. Now, an EPROM
burner for 2716's is DIRT SIMPLE to make, and the same goes for most of the
28-pin parts, and I might guess it's true of the 32-pin parts as well. The
1702's, 2708's, and others of that ilk (mainly due to the multiple power
supplies) might cause minor problems. Those however, can be dealt with in a
number of creative ways.
1) if the goal is to have an "authentic" system, one has to have the
authentic EPROMs with the binary images in them. The spec's for programming
pre-32-pin eproms were not kept secret.
2) if the goal is simply to have a working system, there are several ways to
get around the ancient EPROM oddities. All of these involve wiring and
maybe even soldering something. The easiest of them, however, is to build
an adapter board with the binary images residing in battery backed rams
intended for substitution for EPROMs, and a simple programmer for them for
those situations when things go wrong.
3) Now comes the hard part . . . You have to choose.
Dick
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, October 31, 1999 5:28 PM
Subject: Re: EPROM issues, who can burn?
>> > Ahhhhh... now THAT might get me around the copyright issues! Set it up
>> > such that only the folks who own equipment that can use the images can
get
>> > to it...
>>
>> Well, certainly those folks would be entitled to a copy of what they
>> have already, and it shouldn't be of much value to others.
>
>The time when that's not strictly true is when machines came with
>optional EPROMs...
>
>The classic case is the BBC micro. It has 4 (IIRC) 'sideways ROM
>sockets', one of which is normally filled by the BASIC ROM, and there are
>add-on cards to provide more such sockets.
>
>Various companies (Acorn and others) sold software (disk filing systems
>-- like DOSes, languages, applications, etc) in EPROMs to go into these
>sockets. And while all BBC owners will have had the Acorn MOS (Machine
>Operating System) ROM and BBC BASIC, the same is certainly not true of
>all this other software.
>
>Practically, I suspect that a lot of this software is of little
>commercial value today, but it is still copyrighted, and can't be just
>stuck on a web site.
>
>-tony
>
There certainly were a few vendors whose systems were as much off-center as
the N*. Just take a look at Vector Graphics' systems, for example. I once
owned a couple of those, with their memory-mapped video refresh memory.
They were another box which didn't have enough TPA to run the output
generated from, say, the MT+ Pascal compiler in a unit with a contiguous 64k
RAM.
As I wrote before, the problems went away with the later releases of various
compilers, but while prejudices are easy to acquire, they're difficult to
eliminate.
N* had their own version of a DOS, IIRC, and perhaps that's what made their
management believe they didn't need to offer an efficient and
CP/M-compatible product. Myself, I could never recommend a system which
didn't read/write the standard distribution media for is native OS.
Dick
-----Original Message-----
From: Allison J Parent <allisonp(a)world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, October 31, 1999 8:51 PM
Subject: Re: Northstar Horizon
><Well . . . here we go . . . the fact that N* memory mapped their FDC was
on
><thing that clearly would fall in the MISTAKE category. What the reason fo
><the existence of the smaller TPA resulting from memory mapping anything is
>
>the TPA bit was something I could care less about. The memory mapped
>design was functional, not pretty. Of course the first controller I'd
>built was IOmapped not for more space but because it was easier to decode
>8bits rather than 16. Was it the right way for them, not really but it
>worked. there were plenty of other memory mapped designs that were not
>nearly as nice. It's the way it was right or wrong. So happens I have
>two and one replaced my altair. It was a damm sight better and reliable
>depite two lightiing hits. The only design fault I sought to fix was
>the lack of storage denisty, 80k per drive was far from enough. The later
>controller and software was an improvement but hard sector was a problem
>as it was not even remotely portable. The processor card and the IO on
>the backplane was however very nicely done. Like many I used third party
>ram mostly because I'd alreay had 32k of SEALS 8k static from the altair.
>I still do not ahve NS* ram for the odler box, I'd put in a Compupro
>Ram-16 back in '84 to get rid of the six 8k static and a 16k static.
>Such is the evolution of just one system.
>
><of no relevance. It was a justification for SOME of us, me included, to
><draw a line through their products whenever they appeared in a list. Of
><course their price would have been another.
>
>It was their price that made them attractive. Least on the east coast.
>Some systems like CCS I'd never seen until a few years ago. Others were
>a bit rich price wise or questionable vendors.
>
>Allison
>
Wouter de Waal wrote:
>The 3500 has the following:
>
>9988 rev 3 memory card (no idea of it's size)
>3com ethernet card
>9016 (RGB video adaptor)
>WD7000 scsi/hdd controller
The WD7000 is an ESDI controller
>tape drive
>unknown
>
>Unfortunately I don't have the RGB cable or the monitor.
>
>Questions:
>
>* Can I use the mono display adaptor in the 3500? Can I run one
> of these boxen without a display card, or do they check like
> peecees?
>
>* How ISA compatible is the ISA bus? Can I stick a VGA card in
> there and expect it to work (OK, I know I'll have to write
> the code (port the VGA BIOS) but I mean electrically? Or
> an IDE controller?
>
The bus is completely incompatible with the PC ISA bus. Nothing is likely to
work.
>* Where can I find memory maps, circuit diagrams, whatever?
>
>* How rare are these beasts? I gather they're common? Any
> objections to me ripping out all the cards and the boot
> rom, sticking vmebug in the socket, and an IDE drive in
> the bay, and playing with the thing?
>
I have one I found complete in a dumpster. There were many color monitors
with it but I only took one because they are so huge. It didn't have a
monitor cable with it but I have one from a Decstation that works OK. They
run a unique OS called Domain which I don't have. Mine has a 300meg ESDI
drive and a tape drive. I've had mine up as far as looking for something to
boot from.
Hans
<Well . . . here we go . . . the fact that N* memory mapped their FDC was on
<thing that clearly would fall in the MISTAKE category. What the reason fo
<the existence of the smaller TPA resulting from memory mapping anything is
the TPA bit was something I could care less about. The memory mapped
design was functional, not pretty. Of course the first controller I'd
built was IOmapped not for more space but because it was easier to decode
8bits rather than 16. Was it the right way for them, not really but it
worked. there were plenty of other memory mapped designs that were not
nearly as nice. It's the way it was right or wrong. So happens I have
two and one replaced my altair. It was a damm sight better and reliable
depite two lightiing hits. The only design fault I sought to fix was
the lack of storage denisty, 80k per drive was far from enough. The later
controller and software was an improvement but hard sector was a problem
as it was not even remotely portable. The processor card and the IO on
the backplane was however very nicely done. Like many I used third party
ram mostly because I'd alreay had 32k of SEALS 8k static from the altair.
I still do not ahve NS* ram for the odler box, I'd put in a Compupro
Ram-16 back in '84 to get rid of the six 8k static and a 16k static.
Such is the evolution of just one system.
<of no relevance. It was a justification for SOME of us, me included, to
<draw a line through their products whenever they appeared in a list. Of
<course their price would have been another.
It was their price that made them attractive. Least on the east coast.
Some systems like CCS I'd never seen until a few years ago. Others were
a bit rich price wise or questionable vendors.
Allison
The only way I know to deal with it is to read and then forward the "archive"
files to the owner or person that sent me the EPROM. I have a LABTOOL 48 here
if anyone wants something read - and not just EPROM's. I have not purchased any
adapters yet however. The data for what it will read is at
http://209.24.23.113/products/alldevices.htm What they do with their archive is
their business. If they want to forward back to me an image they want burned I
can't keep track of all the different image files.:)
Definately save all the EPROM's you come across for the above reasons. I never
used to and now I regret it. I am having to scrounge all the time when I need
one.
>one thing I absolutely cannot deal with is a lawsuit!
>
Me either.
Dan
