Re: OpenVMS Alpha V7.3
Well, it took a little bit of monkeying around but I was able to get the the V7.3 ISO I received from a helpful fellow list member to boot on my 3000/400 ... it seems to only like my RRD37 drive and only on the internal SCSI channel ... she is finicky ... but hey, whatever gets the job done :O Woo hoo! Off to load my first Alpha VMS machine! Thanks all! Best, San On Fri, Jul 17, 2015 at 12:55 PM, william degnan billdeg...@gmail.com wrote: thanks for the info. The Alpha in question is a 2100 4/275. It works enough to connect to the web but I need to fix one of the drives. On Fri, Jul 17, 2015 at 12:22 PM, John Willis chocolatejolli...@gmail.com wrote: On Fri, Jul 17, 2015 at 7:53 AM, william degnan billdeg...@gmail.com wrote: related question - I was not able to make a bootable/readable image from the ISO I have 7.3, although it might have been a bad source. Is there a best way/ best software to make a usable 7.3 install CD that will work in an Alpha? Just curious as to why I was not able to make it work. I make CD's all of the time from ISO, but maybe I need to do more research on the subject as far as size and set up go for an Alpha-bootable CD, or CDRW type I need to use, etc. I'd offer my ISO, but I don't know if it's good. Bill Your Alpha system may not support reading burned CDs at all. I know mine doesn't.
Re: Front Panels Sample layout.
White layer 8/e front panels A and B On 17/07/2015 22:23, Adrian Stoness wrote: Sure On Friday, July 17, 2015, Rod Smallwood rodsmallwoo...@btinternet.com wrote: Hi Guys! Further to my previous email. If anybody would like to see the artwork I can send you a copy. Its in *.svg format. Regards Rod
Re: PDP 11 gear finally moved
What I am wondering about, though, is the extra current they draw while they are forming up while the power supply is running. The capacitor might survive it (not get so hot that it fails), but the things supply the higher than ordinary current to it might not. Killed a bridge rectifier on a PDP-12 that way. JRJ On 7/17/2015 1:31 PM, tony duell wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. I am not sure either would have done much good here. The OP said it ran OK for an hour or so, when you test a PSU on dummy load you typically do it for a lot less time than that, Incidentally, DEC PSUs of this type run fine with no load in my experience Also I have found the capacitors in these units to be very reliable. They can fail, of course, but virtually all the DEC bricks I have are on their original capacitors. I think I've replaced more chopper transistors than capacitors in these. -tony
RE: PDP 11 gear finally moved
Rich Alderson ri...@livingcomputermuseum.org wrote: It is generally a good idea to re-form electrolytic capacitors in power supplies, and to bench check the power supplies (under some kind of load) before actually applying power to the whole unit. It is always a good idea to replace electrolytic capacitors in power supplies. The rest of the advice is sound. Rich Rich Alderson Vintage Computing Sr. Systems Engineer Living Computer Museum 2245 1st Avenue S Seattle, WA 98134 mailto:ri...@livingcomputermuseum.org http://www.LivingComputerMuseum.org/ Rich, Can you please clarify if this statement represents the policy of the Living Computer Museum or is it something more personal? Perhaps some qualification or a re-phrasing would be useful as it does not appear to make sense as it stands? I think you may have seen or participated in some of the many discussions we have had on this topic on this list? In light of these discussions, I find it hard to see how a categorical statement such as this one could be justified. Regards, Peter Coghlan.
Re: PDP 11 gear finally moved
Oh, sorry, didn't realize they used switchers for the PDP-11s. However I was talking with a friend of mine last night about my error, and he told me that the switching supplies for the PDP-11s were very unreliable back in the day. He often had to troubleshoot the machines back then. A common failure was caused by static electric shock to the machine would blow the supply. NO carpets allowed!! John :-#)# On 07/17/2015 2:19 PM, Jay Jaeger wrote: U - his PDP-11/34 most certainly does use switching power regulators. ;) On 7/17/2015 4:06 PM, John Robertson wrote: On 07/17/2015 11:53 AM, Mouse wrote: I do find this witch-hunt against capacitors to be curious, given how few I've found to have failed. I suspect a lot of it comes from audiophools who think this is the way to fix anything... Perhaps. But not all of it, certainly. I'm currently four for four fixing dead flatscreens by re-capping their power supplies; I imagine others have similar experiences. It's not a huge stretch to imagine that other power supplies may have similar issues; even if it turns out to not be the case, there is probably at least a little can't hurt anything, right? running around. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B This is not surprising given the vintages of the machines. Modern machines using switching power supplies (15kHz+) must have capacitors with low ESR and high capacity to run properly. Older linear power supplies ran at 50/60hz and as such the capacitors had much less ripple current (and low frequency to boot) to deal with and the engineers typically over designed the values of capacitors to allow for some degradation. The machines you are playing with cost fortunes back in the day - they HAD to be reliable as possible. Modern caps run at or near their rated temperature (105C) last around 1,000 to 5,000 hours. The old linear supplies rarely heated the caps much over 40C and thus the caps would last decades...I put fans on our LCD monitors in our games and they last just fine. No fan? Expect a year or two at most before failure. John :-#)#
RE: PDP 11 gear finally moved
Oh, sorry, didn't realize they used switchers for the PDP-11s. There have been _many_ DEC PSU designed used for the PDP11. I think all of them used some kind of switching regulator for the +5V line. A quick glance at the printsets will settle it.. However I was talking with a friend of mine last night about my error, and he told me that the switching supplies for the PDP-11s were very unreliable back in the day. He often had to troubleshoot the machines back then. A common failure was caused by static electric shock to the machine would blow the supply. NO carpets allowed!! That is (a) meaningless and (b) totally contrary to mine (and others) experiences. It's meaningless because there are so many 'PDP11' power supplies. There are some which use a mains transformer followed by step-down switching regulators. There are some which are more conventional SMPSUs, rectifying the mains and chopping the 350V so produced. There are some which are multiple versions of that in one box (and at least one of those has a switching supply running off the 350V DC rail which produces a single 36V output which is then regulated with more switching regulators). I do not believe all those designs have the same failure modes, or responses to static damage. However, I have worked on many PDP11s, with all sorts of PSUs. Now admittedly I am careful about static, even working on bipolar circuitry. But not to the point of being silly about it. And I will state that I have never damaged (or even caused to trip) a PDP11 PSU by a static zap to any of the output rails. And if a static zap to the casing of the machine damages the supply I would want to check the mains earthing (grounding) -- preferably before a fault causes somebody to get killed. -tony
Re: PDP 11 gear finally moved
More myths and ledgends. As I remember it this all started with the arrival of FET's having a very high input impedance due to narrow gate areas. If you were daft enough not to have a path to earth and let a charge build up on the gate then you could exceed the breakdown voltage across the junction. I used to see the DEC field service statistics and PSU failures due to static build up were rare. Blown filter capacitors and burned up resistors were more the norm. TTL was was not imune to over voltage but not via static build up. Think about a CRT VDU. lots of high voltage and static but no charge up related failures. Rod Smallwood On 18/07/2015 20:31, tony duell wrote: Oh, sorry, didn't realize they used switchers for the PDP-11s. There have been _many_ DEC PSU designed used for the PDP11. I think all of them used some kind of switching regulator for the +5V line. A quick glance at the printsets will settle it.. However I was talking with a friend of mine last night about my error, and he told me that the switching supplies for the PDP-11s were very unreliable back in the day. He often had to troubleshoot the machines back then. A common failure was caused by static electric shock to the machine would blow the supply. NO carpets allowed!! That is (a) meaningless and (b) totally contrary to mine (and others) experiences. It's meaningless because there are so many 'PDP11' power supplies. There are some which use a mains transformer followed by step-down switching regulators. There are some which are more conventional SMPSUs, rectifying the mains and chopping the 350V so produced. There are some which are multiple versions of that in one box (and at least one of those has a switching supply running off the 350V DC rail which produces a single 36V output which is then regulated with more switching regulators). I do not believe all those designs have the same failure modes, or responses to static damage. However, I have worked on many PDP11s, with all sorts of PSUs. Now admittedly I am careful about static, even working on bipolar circuitry. But not to the point of being silly about it. And I will state that I have never damaged (or even caused to trip) a PDP11 PSU by a static zap to any of the output rails. And if a static zap to the casing of the machine damages the supply I would want to check the mains earthing (grounding) -- preferably before a fault causes somebody to get killed. -tony
Re: Looking for keyboard for a BLIT / Teletype / ATT terminal
On Sat, Jul 18, 2015 at 5:53 PM, Ian Finder ian.fin...@gmail.com wrote: Hi Folks, I need help hunting down an item. This is a keyboard that shipped with a few ATT / Teletype terminals with a 6-pin RJ connector. I am also looking for one. I recently cam into a Blit and a 730+ , neither of which had a keyboard. -ethan
STSC APL*PLUS System for VAX VMS User's Reference Manual
For those who expressed an interest in the STSC APL*PLUS manuals for VAX/VMS I happy to report they are now available from here: http://wickensonline.co.uk/static/files/scans/APL-Plus-System-for-the-VAX-VMS-Environment-Users-Manual-Release-1-Aug-1987-STS.pdf http://wickensonline.co.uk/static/files/scans/APL-Plus-System-for-the-VAX-VMS-Environment-Reference-Manual-Release-1-Aug-1987-STS.pdf Apparently the free PC version is very similar to the VAX/VMS version so these manuals should be of direct use. You can run the PC version of APL*PLUS within DOSBox and it is available here: http://www.math.uwaterloo.ca/apl_archives/apl/apl-plus/ Regards, Mark.
Re: PDP 11 gear finally moved
On 07/17/2015 11:17 PM, tony duell wrote: On the other hand if the +5V line did get too high it could have wiped out just about every IC in the unit. Ouch!. I've only ever had this happen once, and it was in a much lesser machine than a PDP11 (fortunately). Many years ago, I managed to feed +12V into an Acorn Atom which was expecting +5V (the on-board regulators were bypassed to allow it to run from an external regulated 5V PSU, rather than the usual unregulated +9V). Amazingly, it survived - although it makes me wonder if the experience dramatically reduced the lifespan of the TTL ICs though, even if they didn't immediately show any failure. cheers Jules
Re: Reproducing old machines with newer technology
- Original Message - From: Chuck Guzis ccl...@sydex.com To: gene...@classiccmp.org; discuss...@classiccmp.org:On-Topic and Off-Topic Posts cctalk@classiccmp.org Sent: Friday, July 17, 2015 12:21 PM Subject: Re: Reproducing old machines with newer technology On 07/16/2015 11:45 AM, Mike Stein wrote: Not the same thing of course but remotely on-topic, and I never miss an opportunity to put in a plug for Cromemco: By comparison, Cromemco used semi-autonomous 4MHz Z80A SBCs for their I/O processors, with 16KB of local RAM and up to 32KB of ROM; communication with peripheral cards is via a separate 50-pin 'C-Bus'. That wasn't all that uncommon in the microprocessor world--once the price dropped sufficiently, doing multiuser applications by giving each user their own CPU was practical. Molecular was another outfit that did practically the same thing. Dual-CPU setups, where the weaker of the two CPUs was in control of the stronger one were even more numerous--just consider the number of add in processor cards for the PC archicture. 68K, NS32xxx...you name a CPU, it's probably been on an ISA card. And there's the veneered and generated Radio Shack 68K series (16, 16B, 6000) where it's the Z80 that starts things and controls the show initially, even if you're running Xenix. In pretty much all cases, the system is capable of running without the stronger CPU. --Chuck - Reply - AFAIK Cromemco never went the 'CPU for every user' route; multi-user systems were implemented using the multi-user Cromix OS, with a 64K memory card for each user in a Z80 system and dynamically allocated memory in a 680x0 system, but always with only one CPU in control. The early versions of Cromix ran on a Z80; when they brought out the dual-CPU Z80/680x0 processor cards you could still run the Z80 version or the 68K version which would use the Z80 as required for Z80 software. When the single 680x0 processor cards came out along with the memory management hardware required to run UNIX they needed a way to still run Z80 (i.e. CP/M or CDOS) software, and that's where the ability to use a Z80 on an I/O controller was handy. I always wondered which was more efficient, multiplexing among essentially complete 'computers per user' sharing a common I/O 'channel' or swapping processes and memory banks... m
Re: Reproducing old machines with newer technology
On 7/18/2015 10:06 PM, Mike Stein wrote: I always wondered which was more efficient, multiplexing among essentially complete 'computers per user' sharing a common I/O 'channel' or swapping processes and memory banks... m I can't think of any system for the average user that runs efficient. Ben. PS: I have a strong dislike of virtual anything.
Re: RE: PDP 11 gear finally moved
So, tony, if I'm correct, you just called bullshit, right? -- --- Dave Woyciesjes --- ICQ# 905818 --- CompTIA A+ Certified IT Tech -http://certification.comptia.org/--- HDI Certified Support Center Analyst -http://www.ThinkHDI.com/Registered Linux user number 464583 Computers have lots of memory but no imagination. The problem with troubleshooting is that trouble shoots back. - from some guy on the internet.
Re: Reproducing old machines with newer technology
On 07/18/2015 09:06 PM, Mike Stein wrote: I always wondered which was more efficient, multiplexing among essentially complete 'computers per user' sharing a common I/O 'channel' or swapping processes and memory banks... Well, the multiplexing (via hardware) memory among a single processor did have the advantage that it was possible to hang a single processor without taking down the whole shebang--you could simply label the processor as unavailable in the processor pool. Believe me, when debugging PPU programs that was very handy--hang a PPU, try again, without rebooting the system. Later versions of the Cyber (e.g. 170/180) actually used separate completely autonomous processors. --Chuck
