test-drb August 2015

test-drb@ccmp.vtda.org

206 participants
257 discussions

by michael.99.thompson＠gmail.com

Date: Thu, 6 Aug 2015 18:43:53 +0100 > From: "Dave G4UGM" <dave.g4ugm at gmail.com> > Subject: RE: Booting an IBM MP 3000 S/390 System > > Actually I remember booting an IBM4381 from cold after we shut it down > over Christmas. Just pressing the Power button powered it up eventually, > but I am pretty sure it took nearly an hour to get to the IPL prompt. So it > did disk drives, then tape drives, then other bits and bobs. But when it > spun up the disks it brought them up one at a time so the startup surges > didn't trip the main breaker. The same with the tape drives. Then it > loaded the microcode into all the controllers. Then it booted the OS. As we > were running VM this last bit took a few seconds (I think). I do know if VM > crashed you screen logo frequently re-appeared before you had time to think. > > Dave Wade > G4UGM > I have done the same on a Honeywell mainframe. After powering up everything manually the only the mag tape and card reader I/O controllers had boot capability. Push the INIT and BOOT buttons and it would read and load tape controller microcode from mag tape, then read and load the disk controller microcode, then the processor's boot code, and then boot from disk. It took just seconds for the mag tape part. Getting the front end processors bootloaded, and getting online communications, timesharing, and batch processing up took a while. This system was capable of booting from binary punched cards. We used to try it periodically just to make sure that this capability worked. -- Michael Thompson

8 years, 9 months

Guy Steele and Emacs - was Re: Classic programming

by jnc＠mercury.lcs.mit.edu

> From: Toby Thain > Peter Siebel's "Coders at Work" features a chapter/interview with > Steele: Ah, thanks for pointing that out; I do have that volume, but I guess I didn't read Steele's chapter. > "So I worked seriously on the implementation of Emacs probably for only > about four or six weeks." That's probably why I didn't know of it - blink and you missed it! :-) Noel

8 years, 9 months

PDP-12 Restoration at the RICM

by michael.99.thompson＠gmail.com

When we first powered up the PDP-12 the main fuse for the VR12 display blew. A replacement fuse did the same. We thought that the brown goo in the bottom of the chassis had leaked from the high-voltage power supply, and the high-voltage power supply is directly connected to the input, so that was the first suspect. We bench tested the high-voltage power supply using a Variac on the input. With a 10VAC input there was no output at all. Increasing the input voltage did not change the missing output voltage. I hate to mention this but... The two capacitors in the voltage-doubler circuit are connected in series between the output lead and ground. We connected a current limited lab power supply to the output lead and ground and slowly increased the voltage while watching the current draw. With the voltage stable the current draw was a few microamps. We increased the output voltage of the power supply to the 64VDC max, disconnected the power supply, and measured the voltage across the caps. It very slowly decreased, so maybe the caps were OK. We reconnected the Variac to the input and with 10VAC the high-voltage power supply had a 1000VDC output. We put 10x 500kOhm resistors in series across the output and increased the Variac voltage. By measuring the voltage across one resistor we could see that the output was more than 10,000VDC. The resistors started smoking so we knew that we had a lot of high-voltage available. So, once again the magic of reforming capacitors saves another piece of equipment. -- Michael Thompson

8 years, 9 months

Qbus split I&D?

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > All I can say is that I did a number of RSX SYSGENs on that 11/34, and > it truly looked just like an 11/24 from a software point of view. The thing that I wonder about it, for that to be true, is something that someone (sorry, to lazy to look in the archive to give proper credit) pointed out, which is that that CPU is only two boards, and the memory management, including the PARs, is built into one of them. So how could one extend a PAR >from 12 bits to 16, when there's already 12 bits buried deep inside the CPU? That's the part that I can't work out... > I'm hoping that Update ... still have the documentation around. You and me both! :-) I have this dream of one day having an 11/45, with the Enable and the optional cache. Now that would be a sweeet machine: most of the capability of an 11/70, but a lot less power draw. But I'd need the documentation to see how to connect it up! :-) > Every time this comes up I really want to go searching for manuals... > :-) Please do! :-) Noel

8 years, 9 months

Qbus split I&D?

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > One more thing to check this summer... OK, if you can, that would really be great; if either i) it's still together, or ii) there are pictures, it would fill some of the key knowledge gaps. In particular, i) what kind of backplane is it plugged into, and ii) what is the UNIBUS edge connector on the card connected to... Noel

8 years, 9 months

Classic programming

by jnc＠mercury.lcs.mit.edu

> From: Kip Koon > I have often wondered what the inspiration for the C Language was. BCPL > -> MCPL -> B -> c, quite an interesting list of languages. I don't think MCPL is in there; B was directly inspired by BCPL. See Dennis M. Ritchie, "The Development of the C Language": http://www.bell-labs.com/usr/dmr/www/chist.html I got the impression from the previous discussion that MCPL was a later branch. Noel

8 years, 9 months

VAX4000/300 MNS7.3 isntallation from CDROM

by holm＠freibergnet.de

Hi, I've got an VAX4000/300 eqipped with an TK70, 2x RF31, 1xRF71 disks, and an CQD-200/TM. I've connected an toshiba Xm5701 drive to the SCSI Bus and the machine sses it as DUA3. I have a VMS7.3 CDROM and want to install it on one of the disks. I've read some documents on HPs website but it isn't clear to me how to boot the cdrom correctly, there is root 1 mentioned. What bootflag must entered, B/R5:10000000? ..in the case w/o the R5:10000000 I get a $ Promt finally (here I habe to read further). With the bootflag the System is complaining that dua3 is write protected (it is the cdrom)... What's the correct way to install VMS on that machine? Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741

8 years, 9 months

OT: Slow booting, was re: Booting an IBM MP 3000 S/390 System

by seefriek＠gmail.com

Supermicros (and to a similar degree Tyan) are mostly in the "server class" of motherboards. That apparently means they put a *lot* of self-test code in there somewhere. I've had literally thousands of Supermicro machines of a dozen different types at various times, and they all took an inordinate amount of time to decide to think about booting no matter what (all auto-detect turned off, quickboot on, inboard SCSI disabled). I got used to it, because quality-wise it was worth the wait.

8 years, 9 months

PDP-12 at the RICM (Michael Thompson)

by michael.99.thompson＠gmail.com

Yesterday we started disassembling the CRT from the VR12. We picked out the silicone that attached the metal bezel to the front of the CRT. The exposed PVA was about 1/8" thick so we picked at the edges to remove as much as possible. We found that the shield was actually loose and were able to remove it without the usual heating or using nasty chemicals. Today we are forming a sheet of 0.093" LEXAN to replace the PVA. It should be a much better implosion shield than the original PVA. Picture here: http://www.ricomputermuseum.org/_/rsrc/1439041136242/Home/equipment/dec-pdp… <http://www.linkedin.com/redir/redirect?url=http%3A%2F%2Fwww%2Ericomputermus…> We tested the high-voltage power supply and it works well. Maybe we can start reassembling and debugging the VR14 this afternoon. -- Michael Thompson

8 years, 9 months

IBM panel... warning

by tmfdmike＠gmail.com

Some of you may remember an IBM System/370 Model 155 panel on eBay a couple of months ago. Something recently prompted me to look that auction up again, and after reading this I decided to warn the list in case it shows up again. The buyer left the following feedback: SCAM! didnt sell 4 enough $, wanted $3000 more outside of eBay after I paid him! IBM System 370 Mainframe front panel (#181771383679)US $727.00 Be warned. Mike http://www.corestore.org 'No greater love hath a man than he lay down his life for his brother. Not for millions, not for glory, not for fame. For one person, in the dark, where no one will ever know or see.'

8 years, 9 months

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test-drb August 2015