In a message dated 7/20/99 2:56:49 PM Eastern Daylight Time,
ard(a)p850ug1.demon.co.uk writes:
> This is even more amusing when the machine in question has an RK05-like
> drive. People won't believe that the 14" packs for one of those are the
> rough equivalent of floppy disks.
LOL! I'll bet you have fun when that situation arises!
> > Yeah, we've got a junk bin full of those cards at the shop, but who
> remembers
>
> Hey, I'm still using them :-)
Right on!
Glen Goodwin
0/0
From: Jerome Fine <jhfine(a)idirect.com>
> Someone who is very experienced has suggested doing a bulk erase
> on a TK50 tape and using it in a TK70 tape drive! Has anyone
> ever done so and what happened?
It's been done. I just bulk-erased a couple of TK50 tapes which had
been written by a TK70 drive so I could use them in a TK50 drive again.
Long ago, I wrote a few TK50 tapes in a TK70 drive and had no problems.
I always use BACKUP /VERIFY.
> I want to decide if a TK70 is the drive for doing backups? It is
> more than twice as fast as a TK50 and the capacity is about
> 4 times when a TK70 is used. Also, the "/VERIFY:ONLY"
> switch in BUP works very well taking less than double the
> time as a straight RESTORE.
The rated capacity of a TK50 is 95MB, and that of a TK70 is 296MB, so
I'd say 3X is closer than 4X. The TK50 tapes can be read by either
drive type, but it's slower, and you need more tapes that way. What's
more important to you?
Not to sound ignorant, but "BUP"? "/VERIFY:ONLY"?
------------------------------------------------------------------------
Steven M. Schweda (+1) 651-645-9249 (voice, home)
1630 Marshall Avenue #8 (+1) 612-754-2636 (voice, work)
Saint Paul MN 55104-6225 (+1) 612-754-6302 (facsimile, work)
sms(a)antinode.org sms(a)provis.com (work)
Someone who is very experienced has suggested doing a bulk erase
on a TK50 tape and using it in a TK70 tape drive! Has anyone
ever done so and what happened?
I want to decide if a TK70 is the drive for doing backups? It is
more than twice as fast as a TK50 and the capacity is about
4 times when a TK70 is used. Also, the "/VERIFY:ONLY"
switch in BUP works very well taking less than double the
time as a straight RESTORE.
Can anyone else comment please?
<The previous mentioned article in Byte is "Coincident Current Ferrite Core
<Memories" and is in the July, 1976 Issue. It is very helpful. It describes
That's the one. Lost my copy (a whole xerox paper box of 3+years) two major
moves ago. A copy of that would be of some help. Finding patterns for
stringing the core plane is tough.
Allison
Unfortunately the "few weeks' training you get from programming the VGA
chips on most display boards is worth less than nothing because it's
consuming too much time and effort and using time which could be used in
more valuable pursuits. I can assure you that soldering a resistor onto the
back of a display adapter is sufficient to verify that the monitor can be
used, and no programming of any sort is needed. If the card is capable of
60 Hz non-interlaced 1280x1024x256-color display, programming it won't be
necessary, as it will support that format. If it's not, all the programming
either of us could do won't help.
The sync mixer I have used, and instructed others to use, many times since
the mid-to-late '80's is quite simple, uses a current mirror, a dif-amp, and
a couple of diodes configured as a negative logic OR, with the aid of a half
dozen resistors. It's a circuit any first year EE student should be able to
build and fully understand. If the first year EE student can do it, so can
anyone else! It was probably designed by a student and then cleaned up by
the guys at Brooktree, from one of whose app-notes I pinched the circuit
back in days of old. I had to add details about the hookup, but it's
essentially their circuit. The benefit is that it will happily tolerate
either polarity of one or the other sync signals if you fiddle with it a
bit.
I'd not consider trying to program this display format in to a board which
doesn't normally support it because that normally indicates it isn't
capable. You might want to get out your slide rule and figure out how fast
the pixels have to fly out of the DAC if you want 1280 of them in the active
portion of a 64kHz sweep. Most of them (the boards in question) simply
won't do that.
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: Tuesday, July 20, 1999 1:05 PM
Subject: Re: Sun Monitor (UK) (2)
>>
>> Having had a while to recall, I believe the SONY, formerly attached to a
SUN,
>> did, indeed, have five BNC inputs on it. However, in order to get the
>> display board and the monitor to "play" together, it was easier to use
only
>> three of them because, in the absence of SYNC on the last two BNC's it
>> happily responded to negative-going sync on GREEN. I'm not sure whether
>
>This is certainly going to be a YMMV thing, so I think it's best if I
>make my comments as well, and whoever is trying to get the monitor
>working can pick which one they prefer...
>
>I prefer to use separate syncs where possible. For one thing it
>eliminates the sync mixer and separator stages. For another, it gives me
>nice simple signals to trigger a 'scope off when I have problems.
>
>Inverting a TTL signal (particularly one < 1MHz) is IMHO a lot easier
>than making a sync mixer which has to handle video signals aproaching
>100MHz. Still, it's up to you.
>
You're right, it is easier, but this circuit is already designed and proven.
It simply needs to be built faithfully to the schematic and such that it
looks good. So long as there are no excessively long (meaning longer than
absolutely necessary) wires, and so long as the soldering is neat and clean,
everything should go well.
>
>> All the points you've made are well considered, which is why I suggested
you
>> start with the resistor to green just to see whether you can use this
>> monitor with the cards you own. It's really not worth the effort to make
a
>> card not already capable of the right scan rates do the job if you have
to
>> reinvent the display board's BIOS, as that vendor in southern California
>> does. At 50 cents per hour, the effort will approach the national debt.
A
>> really decent 19" monitor compatible with most any current VGA card costs
>> $400 at the Best-Buy or whatever other discount store you like. There is
a
>> point beyond which even I, frugal as I am, won't wander.
>
>You've forgotten the education you'll get doing this :-). You'll learn
>about programming VGA chips, working with video/sync signals, maybe
>getting inside the monitor and tweaking the scan rates, etc.
>
at $1(US) per hour you'll save a fortune by buying a good 20" monitor at a
computer store. You'd be better off shining shoes for it than trying to
program a board which doesn't already do what you want.
>
>Or at least that's how I justify spending a few weeks mending something
>when I could buy one for a few pounds down at the local PC shop :-)
>
Don't they say, "penny-wise, pound-foolish" where you live?
>
>-tony
>
On Jul 20, 22:15, Tony Duell wrote:
> Subject: Re: SSB DOS68? Anyone? Anyone?
> >
> > On 20 Jul 99, at 16:33, Bill Yakowenko wrote:
> > > Heck, while I'm begging, does anybody out there have Flex for
> > > the Radio Shack Color Computer?
> >
> > No but I wish I did. If you locate a source let us know.
>
> I've just found what I think is the Flex-09 boot disk for an Acorn 6809
> system...
Aha! Tony, can I have a copy of that? BTW, did you ever dig out the other
6809 bits for me? I suppose that means I'll have to type in that ROM
listing now...
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
From: yakowenk(a)csx.unxc.edu (remove all x's)
I just got e-mail from a guy reviviing an old SWTPC 6800 box
with SSB disk drives. He now has the CPU working, but his old
DOS68 disks won't boot. Does anyone out there have a copy that
they would be willing to send him? If so, reply to him directly
at: bxrinxson(a)us.ibm.com (remove x's).
For that matter, I hope to be in a similar situation in a couple
weeks, except that I have the SWTPC drives and controller rather
than the SSB ones. Anybody want to send me boot disks for that?
Heck, while I'm begging, does anybody out there have Flex for
the Radio Shack Color Computer?
Cheers,
Bill.
http://www.can.ibm.com/helpware/8590.html
In a message dated 7/20/99 3:38:41 PM Eastern Daylight Time,
rhblake(a)bigfoot.com writes:
> Also for anyone interested in what a 90 looks like or specs, go to
> http://members.tripod.com/~ps2page/ and click on the appropriate area.
>
> Joe wrote:
>
> > Does anyone want an IBM PS/2 model 90 XP 486? I have one that needs a
> > home. It's supposed to work but I haven't tested it. If someone wants it,
> > I'll check it out. This one has a built-in tape drive. I don't know if
> > that's standard on the model 90 or not but it certainly looks like it
came
> > from the factory that way. Trades or $$$ welcome.
> >
> > Joe
>
Having had a whileto recall, I believe the SONY, formerly attached to a SUN,
did, indeed, have five BNC inputs on it. However, in order to get the
display board and the monitor to "play" together, it was easier to use only
three of them because, in the absence of SYNC on the last two BNC's it
happily responded to negative-going sync on GREEN. I'm not sure whether
there was a switch to enable this function. The monitor on the floor next
to me has such a switch and I was using it up until a few weeks ago, and for
seven or eight years, so it's likely I'll occasionally confuse it with my
SONY experience. The one on the floor is a multisync-capable Hitachi with
both the DE15 and the 5 BNC's on it with a switch to select which it uses.
All the points you've made are well considered, which is why I suggested you
start with the resistor to green just to see whether you can use this
monitor with the cards you own. It's really not worth the effort to make a
card not already capable of the right scan rates do the job if you have to
reinvent the display board's BIOS, as that vendor in southern California
does. At 50 cents per hour, the effort will approach the national debt. A
really decent 19" monitor compatible with most any current VGA card costs
$400 at the Best-Buy or whatever other discount store you like. There is a
point beyond which even I, frugal as I am, won't wander.
I'd advise you to find a card which looks like it works at a non-interlaced
60Hz vertical and approximately 64kHz horizontal sweep and negative going
sync. If it has the rate but not the polarity, don't fiddle with the
firmware, just attach the resistor as I suggested and see what you get on
the display. If that works, then maybe you should build an adapter which
serves more appropriately and safely for the long run. (The resistor never
impressed me as particularly good for the display board.) You can easily
build a perfectly solid adapter using a CA3127 or equivalent HF transistor
array and a few resistors which will adapt your display board capable of a
suitable sweep rate to "WINDOWS-compatible" sweep rates. If you want more
than that, perhaps you're beating a dead horse.
Dick
-----Original Message-----
From: Lawrence Walker <lwalker(a)mail.interlog.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, July 20, 1999 5:26 AM
Subject: Re: Sun Monitor (UK) (2)
On 19 Jul 99 at 18:48, Richard Erlacher wrote:
> What I meant was that IF your monitor has only three BNC's, as my formerly
> SUN SONY GDM1950 19" monitor did, then you need to impose negative-going
> composite sync on the GREEN Video output of your VGA/XGA card. IF your
> monitor has five BNC's on the back, then any reasonably close to 60Hz
> vertical and 64kHz horizontal sweep rate will probably work fine.
> Unfortunately, since these are fixed frequency monitors with a VERY fine
> pitch and a VERY linear sweep and a VERY easy-to-converge system, one
price
> you pay is that you can only use them at the ONE sweep rate for which they
> were designed or close to it.
>
> If you have the five BNC's, then you need an adapter cable which has the
HD
> DE15 connector at one end and, guess what, the five BNC's emanating from
it.
> These should have RED, GREEN, and BLUE, with the respective returns on
each
> 75-ohm coax, and HSYNC and VSYNC, negative-going from ground, by the way,
> but that may not matter as they're AC coupled at the monitor.
>
> Since you can buy the adapter for about $20 here in the US, I doubt
they're
> much different there in the UK. In any case, you've avoided any soldering
> other than at the cable if you build it yourself.
>
I use a 5 BNC to VGA adaptor with my NEC now so that's no problem.
The Sony GDM1950 designation is strange. Yours was a Sun, mine is a SuperMac
and in searching the net I also found references to a Radius version, whom I
had thought manufactured their own monitors. There seem to be 19-21"
versions
and now I find also 3 and 5 BNC editions. Makes finding specs difficult. I
found this reference in the Sync on green FAQ :
"For example, a STORM 1280/256 will drive a Sony GDM-1950 at 640x480,
800x600,
1024x768, 1280x1024 and DOS modes (this monitor is rated at 63.34Khz
Horizontal
sync. and the card runs at 64Khz Horizontal sync.). This card uses an S3
graphics accelerator. See also PC Magazine/April/13/1993."
Now what kind of bloody "fixed frequency" is this. On another site ISTR they
even had a different scan rate.
> If you need a circuit suitable for the three BNC arrangement, I actually
> have a really solid one using an HF transistor array and a negative
supply,
> which, by the way, is on the motherboard, so neatly attaching it to the
> video card isn't too unrealistic. For just checking it out, I'd suggest
the
> 500-ohm resistor, though, provided you can find an application (that's the
> formerly edge-connector at the top of the VGA cards of yesteryear. They
had
> 16 pins as do the current pin fields, so you'll find from old doc's which
> one's the composite blanking.) connector somewhere.
>
Ah, now I see what your referring to. Usually called a "feature" connector
by
IBM.
> If the monitor has all the signals entering via the 5 BNC's you just need
to
> fiddle with the VGA card's operating mode to get it into a 60Hz
> non-interlaced mode. Many of the newer VGA's won't do this, so read the
> spec's carefully! The older ones which did produce the high frequency dot
> clock required were expensive, and the newer ones don't have fast enough
> DAC's to do the job, so shop carefully, and make sure you can return the
> board if you buy one. IT MUST BE CAPABLE OF 1280 x 1024 lines at 60Hz
> without interlace!
>
> Good Luck!
>
> Dick
>
I'll likely bite the bullet and just try it on the old MCA ATI MACH 32 card
(which also has the "feature" connector BTW) in my PS2 8580 after seeing
what
info I can pry out of ATI who are based here in Toronto.
Thanks.
ciao larry
lwalker(a)interlog.com
Let us know of your upcoming computer events for our Events Page.
t3c(a)xoommail.com
Vintage Computer Collectors List and info http://members.xoom.com/T3C
On 19 Jul 99 at 18:48, Richard Erlacher wrote:
> What I meant was that IF your monitor has only three BNC's, as my formerly
> SUN SONY GDM1950 19" monitor did, then you need to impose negative-going
> composite sync on the GREEN Video output of your VGA/XGA card. IF your
> monitor has five BNC's on the back, then any reasonably close to 60Hz
> vertical and 64kHz horizontal sweep rate will probably work fine.
> Unfortunately, since these are fixed frequency monitors with a VERY fine
> pitch and a VERY linear sweep and a VERY easy-to-converge system, one price
> you pay is that you can only use them at the ONE sweep rate for which they
> were designed or close to it.
>
> If you have the five BNC's, then you need an adapter cable which has the HD
> DE15 connector at one end and, guess what, the five BNC's emanating from it.
> These should have RED, GREEN, and BLUE, with the respective returns on each
> 75-ohm coax, and HSYNC and VSYNC, negative-going from ground, by the way,
> but that may not matter as they're AC coupled at the monitor.
>
> Since you can buy the adapter for about $20 here in the US, I doubt they're
> much different there in the UK. In any case, you've avoided any soldering
> other than at the cable if you build it yourself.
>
I use a 5 BNC to VGA adaptor with my NEC now so that's no problem.
The Sony GDM1950 designation is strange. Yours was a Sun, mine is a SuperMac
and in searching the net I also found references to a Radius version, whom I
had thought manufactured their own monitors. There seem to be 19-21" versions
and now I find also 3 and 5 BNC editions. Makes finding specs difficult. I
found this reference in the Sync on green FAQ :
"For example, a STORM 1280/256 will drive a Sony GDM-1950 at 640x480, 800x600,
1024x768, 1280x1024 and DOS modes (this monitor is rated at 63.34Khz Horizontal
sync. and the card runs at 64Khz Horizontal sync.). This card uses an S3
graphics accelerator. See also PC Magazine/April/13/1993."
Now what kind of bloody "fixed frequency" is this. On another site ISTR they
even had a different scan rate.
> If you need a circuit suitable for the three BNC arrangement, I actually
> have a really solid one using an HF transistor array and a negative supply,
> which, by the way, is on the motherboard, so neatly attaching it to the
> video card isn't too unrealistic. For just checking it out, I'd suggest the
> 500-ohm resistor, though, provided you can find an application (that's the
> formerly edge-connector at the top of the VGA cards of yesteryear. They had
> 16 pins as do the current pin fields, so you'll find from old doc's which
> one's the composite blanking.) connector somewhere.
>
Ah, now I see what your referring to. Usually called a "feature" connector by
IBM.
> If the monitor has all the signals entering via the 5 BNC's you just need to
> fiddle with the VGA card's operating mode to get it into a 60Hz
> non-interlaced mode. Many of the newer VGA's won't do this, so read the
> spec's carefully! The older ones which did produce the high frequency dot
> clock required were expensive, and the newer ones don't have fast enough
> DAC's to do the job, so shop carefully, and make sure you can return the
> board if you buy one. IT MUST BE CAPABLE OF 1280 x 1024 lines at 60Hz
> without interlace!
>
> Good Luck!
>
> Dick
>
I'll likely bite the bullet and just try it on the old MCA ATI MACH 32 card
(which also has the "feature" connector BTW) in my PS2 8580 after seeing what
info I can pry out of ATI who are based here in Toronto.
Thanks.
ciao larry
lwalker(a)interlog.com
Let us know of your upcoming computer events for our Events Page.
t3c(a)xoommail.com
Vintage Computer Collectors List and info http://members.xoom.com/T3C
