test-drb January 2009

test-drb@ccmp.vtda.org

218 participants
340 discussions

by bqt＠softjar.se

Since there have been a few discussions about the memory/cache of the 11/70 now, I think I might make a few comments as well. When we talk about the MK11 memory, you need to remember that it's a separate memory box, and is not at all transparent to the 11/70. The 11/70 have a memory bus. This memory bus is what you would interface to if you designed your own memory which you put in the free CPU slot. The memory bus don't have any ECC. The ECC of the MK11 is totally located inside the MK11, and is not visible outside. The 11/70 memory bus only have parity bits. So you can skip all the ECC stuff if you want to play with your own memory "box" design. Pretend it's a MJ11 instead, which is simpler. Another detail is that memory refresh is also something that is internal to the box. None of that is visible to the CPU. And neither is memory rewrites in the case of core. Now, my memory of the 11/70 memory bus is fuzzy, since it's been quite a while since I was studying it. But the schematics and manuals are out there, so all of this can be read up on. But as far as I remember, the 11/70 memory bus is rather simple and asynchronous. The machine presents 22 address (actually 24 are defined, but the top two are always zero). You have 32 data bits. 4 parity on data, and probably also parity on address. You have a few control lines, and that's it. You have three types of transactions. Read, Write, and Read-modiy-write. With the 11/74 you also have an interlock function, but I guess that's a moot point since noone around here have an 11/74 CPU anyway. However, the 11/70 cache and memory controller presents quite a lot of overhead and slowdown. If you really would like to speed the 11/70 up (and you can, believe me), you would want to replace the cache and memory controller all together. Now, after reading a few comments here, I've finally understood the relationship between the SETASI PEP-70 and HC-70. The PEP-70 is 4 megs of memory. You can connect that to the 11/70 memory bus. The HC-70 replaces the cache and memory controller in the CPU. This makes the whole 4 Meg of memory look like cache. You hook the PEP-70 to the HC-70 instead. Nice solution actually. I wonder if (in theory) you could hook any memory box to the HC-70, or if the PEP-70 can work in two modes. One as a device on the memory bus, and one as a cache memory for the HC-70. Anyway, if someone were to design a memory system for the 11/70, the way I'd recommend is to go the whole way, since that's where the real gains are. Skip the memory bus and the original cache. The original cache is just 2 KB of 2-way associative memory. If you set up a 4 MB cache, the CPU can run at full steam the whole time, with a cycle time of about 150 nS, if I remember right. It is more complicated, though. You'll have access paths from CPU, Unibus and four massbus controllers to deal with. But it should definitely be doable (heck, SETASI have already done it once). I might be interested in such a project myself, since the 11/70s we have around here still are on MK11 boxes. I could deal with PCBs and design, but I'm very short on time, as usual... :-( No experience at all with FPGAs or any such fancy stuff. Johnny

15 years, 4 months

Arcades becoming extinct..

by bryan.pope＠comcast.net

.. if they haven't already! :-( I used to always go to this arcade when I was in Toronto (Funland Arcade on Younge Street)... http://www.citynews.ca/news/news_19730.aspx Now its gone.. :-( http://arcadeheroes.com/2008/07/10/funland-arcade-in-toronto-canada-closing… http://www.thestar.com/comment/columnists/article/453843 Syd Bolton of the Personal Computer Museum ( http://www.pcmuseum.ca/ ) of Brantford, Ontario on the last day: http://www.youtube.com/watch?v=QxA2WRqtUkk Cheers, Bryan

15 years, 4 months

PDP-8/e, DECtape TU56 and other stuff available

by erikb＠digischool.nl

Hi folks, Available in the Netherlands for a reasonable offer: PDP-8/e computer PDP-11/40 computer and spare PDP-11/40 processor board set TU56 DECtape unit TC11 UNIBUS DECtape controller PC05 paper tape unit with PC11 UNIBUS controller PDP-9 and PDP-12 consoles Circa 500 M/G/W series single height flip-chips HP 9100 programmable calculator Tektronix 4051 graphics computer Everything looks pretty good, but except for the HP 9100 nothing has been switched on. Please contact me directly if interested. Sincerely, Erik.

15 years, 4 months

FS: NeXT Turbo in Seattle WA area

by michaelgreen42＠comcast.net

I am getting ready to move and trying to lighten my load a bit. I have a working NeXT Turbo, 17 b/w monitor, keyboard, and mouse. It works great with a few minor issues. It boots but gets stuck on detecting network. Since I can't find my NeXTStep install CD's I can't log into it anyway since I don't know the password. Also the port where the mouse plugs into the keyboard has separated from the keyboard portion. It can be fixed since it's not actually broken but it will take more patience/time than I have or just a new keyboard. Looking for best offer. If you don't want the monitor due to shipping reasons I can take that off.

15 years, 4 months

Interesting Folder

by wdonzelli＠gmail.com

I am culling thru some IBM docs, and came across a boring printer memo (for the 3203, all about print quality, big deal) bound in an interesting binder. It is a standard 1950s brown Accopress binder, but the tag on the front says "FRAME 41, XD-1 MAINTENANCE SUPPORT, GROUP 201-250". This cam from a gut that gave RCS a big pile of IBM docs (he was an FE) in the Boston area. XD-1 as in AN/FSQ-7(XD-1)? Mike? -- Will

15 years, 4 months

Mac SE FS in Seattle Area

by michaelgreen42＠comcast.net

I've got a number of working Mac SE's (not 30's) I'd like to sell. I've got both HD and dual floppy models. Some of them need an OS reload and some work fine. Make me an offer, I'd like to move these soon due to a pending relocation.

15 years, 4 months

Lifting heavy rack-mount gear (was Re: PDP-8/e rack questions)

by steve＠cosam.org

2009/1/6 Dave McGuire <mcguire at neurotica.com>: > On Jan 5, 2009, at 5:37 PM, Henk Gooijen wrote: >> That is how my TU56 is hung in the H960 rack. You need help to >> mount the TU56. I did it alone, and remember that is was heavy >> to do on my own, hanging the TU56 in the 5th 10.5" position, >> counting from the bottom :-) > > I did mine alone as well. It is definitely a very heavy machine. I had > back pains for days after doing that. > Probably hard to justify the cost for occasional use, but I'd really like to get one of these before I do myself any permanent damage: http://www.edmolift.co.uk/lift_trolleys.htm [link to random supplier of lift trolleys] I reckon you could slide out your kit, then pump that thing up underneath before undoing the screws. Replacement is the reverse of the removal procedure, as they say. -- Steve Maddison http://www.cosam.org/

15 years, 4 months

Arcades becoming extinct..

by evan＠snarc.net

Sad indeed. Brings back happy memories though of my own childhood arcade in a room at the local bowling alley. The arcade is long gone ... and the bowling alley is a Pathmark. Mark my words ... if MARCH ever gets massive H-building space and a steady stream of visitors, then there shall be a legit arcade room!!! ------Original Message------ From: Bryan Pope Sender: cctalk-bounces at classiccmp.org To: General Discussion On-Topic and Off-Topic Posts ReplyTo: General Discussion: On-Topic and Off-Topic Posts Subject: Arcades becoming extinct.. Sent: Jan 10, 2009 1:05 AM .. if they haven't already! :-( I used to always go to this arcade when I was in Toronto (Funland Arcade on Younge Street)... http://www.citynews.ca/news/news_19730.aspx Now its gone.. :-( http://arcadeheroes.com/2008/07/10/funland-arcade-in-toronto-canada-closing… http://www.thestar.com/comment/columnists/article/453843 Syd Bolton of the Personal Computer Museum ( http://www.pcmuseum.ca/ ) of Brantford, Ontario on the last day: http://www.youtube.com/watch?v=QxA2WRqtUkk Cheers, Bryan

15 years, 4 months

DEC Direct Sales Catalog

by silent700＠gmail.com

I have a copy of this book: http://flickr.com/photos/chiclassiccomp/3178202349/ It appears to be from around 1979, and is chock full of part numbers and specs for hundreds of DEC products of the time, including rack parts, documentation kits, and even the DECMat carpet :) I would really like to get this book scanned, OCR'd and available to DEC collectors. My questions are: Has this guide, or one close to it, already been scanned? How rare are these guides? Does anyone out there have one? I would have to at least remove the binding in order to scan it (and at 140 pages I'm not going to mash each half-page against the scanner glass.) I'd really hate to destroy a book like this. If I'm careful, I can drill holes in the whitespaces, razor off the edge binding, and reassemble it as ringbound.

15 years, 4 months

Arcades becoming extinct..

by evan＠snarc.net

>>> The arcades of today may be disappearing, but the arcades of yesterday are actually on the rise. There is an excellent "new school" store / arcade called Digital Press, located in Clifton, N.J. ... It's about a 45-minute drive from Newark Airport if anyone has a long layover and rental car.

15 years, 4 months

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test-drb January 2009