On 2014-01-15 15:42, Cory Smelosky wrote:
On Wed, 15 Jan 2014, Dave McGuire wrote:
On 01/15/2014 06:35 PM, Cory Smelosky wrote:
A lot of people (myself included) insisted on direct-in-the-bus
printer controllers when we saw how badly serial printers tanked the
system when we connected them to DZ11s. ;)
Oh I can imagine that. A dedicated controller would have MUCH higher
bandwidth than the <1.5mbitcapable on the DZ11. ;)
It's the interrupt load that's the problem. It could TANK an 11/750.
Didn't the DZ11 depend on the CPU for interrupts?
Eh... Every controller depends on the CPU for interrupts. That's what interrupts mean.
However, the problem with the DZ11 is that it generates interrupts for each character sent as well as each character received. It do have some smart in it, so you can get a few characters per interrupt under some circumstances, but the interface basically just killed a machine when you did lots of I/O, because of the interrupt load.
Isn't that why say...the DHV11 had processors to offload serial
processing to?
DH11, DHV11 and DHU11 all use DMA for output, meaning you only get one interrupt when the output is done. Which is *way* better.
Johnny
On 2014-01-15 15:31, Dave McGuire wrote:
On 01/15/2014 06:27 PM, Cory Smelosky wrote:
The LA180 has more in common with the LA120 than the LA36. There is
also a serially-interfaced variant of the LA180, which has a
serial-to-parallel (*NOT* "Centronics" parallel, for others reading
this) converter board mounted internally.
That's...quite interesting. Why is it parallel internally...
Because the primary intended configuration for those printers is with
dedicated printer controller boards like the LP11, LPV11, and LS11.
Ahhhhh. Interesting design choice, to be honest. I bet it was a bit
proprietary though....fast as well.
Of course it's proprietary. You ordered a printer from DEC when you
ordered your computer from DEC. It was a very different world back then.
A lot of people (myself included) insisted on direct-in-the-bus
printer controllers when we saw how badly serial printers tanked the
system when we connected them to DZ11s. ;)
Heh! The DZ-11 is a hog. We all know that.
But the LP11 is not really much better. It's also interrupt per character unless I remember wrong. But it's only one printer per card, and no input. And of course, much faster, since it's parallel with handshaking.
Johnny
On 2014-01-15 15:28, Brian Schenkenberger, VAXman- wrote:
The LA120 was the de facto console terminal for the VAX-11/78*s. One reason
why I have three; albeit, one has been cannibalized for parts.
Also standard on PDP-11s as well as DECsystem-10 and DECsystem-20 machines...
Update have at least three... (Or had, last I looked. Two with 20mA and one with RS-232.)
Johnny
On 2014-01-15 15:27, Cory Smelosky wrote:
On Wed, 15 Jan 2014, Dave McGuire wrote:
On 01/15/2014 06:00 PM, Cory Smelosky wrote:
The LA180 receive-only printer was, I think, a derivative of the
LA36, not the LA120. The 1976 Peripheral handbook seems to support
that. Note that there also was an LA35, a receive-only variant of
the LA36. The difference is that the LA35 had a serial interface
while the LA180 had a parallel (line printer style) interface.
The LA180 has more in common with the LA120 than the LA36. There is
also a serially-interfaced variant of the LA180, which has a
serial-to-parallel (*NOT* "Centronics" parallel, for others reading
this) converter board mounted internally.
That's...quite interesting. Why is it parallel internally...
Because the primary intended configuration for those printers is with
dedicated printer controller boards like the LP11, LPV11, and LS11.
Ahhhhh. Interesting design choice, to be honest. I bet it was a bit
proprietary though....fast as well.
The interface on the LP11 is extremely close to Centronics. You need to invert a signal or two (I don't remember the details, but I did this many years ago for an LP8 controller). After that, you're all set.
It's much faster than serial, but no speed daemon.
Johnny
On 2014-01-15 15:17, Brian Schenkenberger, VAXman- wrote:
Mark Wickens <mark at wickensonline.co.uk> writes:
So, out of interest, what was the last/most reliable/most desirable DEC
true line printer - i.e. chain/band rather than matrix?
My first year at college ~ 1990 included VAX/Pascal programming with
assignments printed to a true line printer.
Happy times in that lovely warm computer room on cold, dark winter days...
IMHO, the LXY21!
Never used that one, but my experience with the LP26 and LP27 are good. I never had any problems with them. Never had problems with the LP14 either, as far as I can remember, but it was a beast.
Johnny
On Wed, 15 Jan 2014, Dave McGuire wrote:
On 01/15/2014 06:57 PM, Cory Smelosky wrote:
Note that these are larger-than-normal racks, and they're very
difficult to move. They weigh about 1200lbs. I've moved a pair of
these machines by myself without proper equipment, and thus at great
personal risk, to my old place a few years ago. I did so out of
necessity. The story (with pics) is here:
http://www.neurotica.com/wiki/Sun_Fire_6800_Unload
DO NOT TRY THIS AT HOME. I could very easily have gotten killed in
that operation. "Regular" racks are one thing...these weigh well over
half a ton, and are a different matter entirely.
Well, I'll stick it in the room where a piano used to sit. It should
hold there. ;) (Also no need for stairs, then.)
Measure the doorways. I have to rent special trucks to move 6800s due
to their height. If memory serves, they are 76" tall.
I think that would barely fit. Maybe i'll want to build a little shed for it. ;)
I could also fairly easily rig something up with a switch to change
between that and the oven, then...as nowhere else would I have minimum
30A service save for upstairs and the air conditioner. ;)
You'll have to do more than that. That machine has FOUR 230V 30A
power cables. It can run on two.
That would be a bit harder to manage. ;)
Getting to 230V is easy. Getting to 230V with 30A each is harder.
-Dave
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
On 01/15/2014 06:57 PM, Cory Smelosky wrote:
Note that these are larger-than-normal racks, and they're very
difficult to move. They weigh about 1200lbs. I've moved a pair of
these machines by myself without proper equipment, and thus at great
personal risk, to my old place a few years ago. I did so out of
necessity. The story (with pics) is here:
http://www.neurotica.com/wiki/Sun_Fire_6800_Unload
DO NOT TRY THIS AT HOME. I could very easily have gotten killed in
that operation. "Regular" racks are one thing...these weigh well over
half a ton, and are a different matter entirely.
Well, I'll stick it in the room where a piano used to sit. It should
hold there. ;) (Also no need for stairs, then.)
Measure the doorways. I have to rent special trucks to move 6800s due
to their height. If memory serves, they are 76" tall.
I could also fairly easily rig something up with a switch to change
between that and the oven, then...as nowhere else would I have minimum
30A service save for upstairs and the air conditioner. ;)
You'll have to do more than that. That machine has FOUR 230V 30A
power cables. It can run on two.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
On 2014-01-15 14:18, Brian Schenkenberger, VAXman- wrote:
Johnny Billquist <bqt at softjar.se> writes:
On 2014-01-14 03:44, Sampsa Laine wrote:
sampsa <sampsa at mac.com>
mobile +44 7961 149465
On 14 Jan 2014, at 13:42, "Brian Schenkenberger, VAXman-" <system at TMESIS.COM> wrote:
Sampsa Laine <sampsa at mac.com> writes:
Anybody know what happened with that discussion re: EISNER and HECnet?
Also, is EISNER even up any more? I can't seem to connect to it.
EISNER is being or has been physically relocated. Once it is back up, I'll
see what can be done about getting it connected to HECnet. I have no idea
what'll be available network-wise/router-wise until EISNER is back on-line.
Mind you with such a large change anyway, it might be a good time to "sneak in" the connection to HECnet :)
I totally dislike the "sneak in" comment. If it is going to happen, it
must be done very openly and consciously. Noone will benefit from trying
to sneak something in.
Once Eisner has been reconnected and revived -- seriously, I do not know
why this relocation effort is taking so long -- I will communicate with
the new caretakes about their router config; hopefully, it's a Cisco box
that can support the DECnet tunnel. I doubt that there would be a Linux
box there that would serve as a gateway.
If they are running Multinet, you could also setup a link using that.
Johnny
On Wed, 15 Jan 2014, Dave McGuire wrote:
On 01/15/2014 06:42 PM, Cory Smelosky wrote:
A lot of people (myself included) insisted on direct-in-the-bus
printer controllers when we saw how badly serial printers tanked the
system when we connected them to DZ11s. ;)
Oh I can imagine that. A dedicated controller would have MUCH higher
bandwidth than the <1.5mbitcapable on the DZ11. ;)
It's the interrupt load that's the problem. It could TANK an 11/750.
Didn't the DZ11 depend on the CPU for interrupts?
Every interrupt depends on the CPU. ;)
True...but offloading helps cut down on the other stuff it needs to process. ;)
Isn't that why say...the DHV11 had processors to offload serial
processing to?
The DHV11 has a pair of 8051s on it. The DH11 is several boards full
of logic. It has buffering and DMA capability to offload the host
system...it needs much less hand-holding than the DZ11.
Ahh. I thought it was something like that.
-Dave
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
On Wed, 15 Jan 2014, Dave McGuire wrote:
On 01/15/2014 06:41 PM, Cory Smelosky wrote:
I'll gladly take a 6800. ;)
I can make COMPLETE use of 24 processors! As it'll take a IV...that's
dual-core right? Meaning...48 cores!
Even the processors that are in them have GREAT BIG CLANGING BALLS. I
just have no use for them here. If you want one, you can have one. I
will deliver it to your driveway, but you must bear the expense. That
will primarily consist of truck rental fees and fuel. I could probably
get one to you for about $250.
That isn't that bad. I could handle that with time.
Note that these are larger-than-normal racks, and they're very
difficult to move. They weigh about 1200lbs. I've moved a pair of
these machines by myself without proper equipment, and thus at great
personal risk, to my old place a few years ago. I did so out of
necessity. The story (with pics) is here:
http://www.neurotica.com/wiki/Sun_Fire_6800_Unload
DO NOT TRY THIS AT HOME. I could very easily have gotten killed in
that operation. "Regular" racks are one thing...these weigh well over
half a ton, and are a different matter entirely.
Well, I'll stick it in the room where a piano used to sit. It should hold there. ;) (Also no need for stairs, then.)
I could also fairly easily rig something up with a switch to change between that and the oven, then...as nowhere else would I have minimum 30A service save for upstairs and the air conditioner. ;)
-Dave
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
