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Build your own PDP 8I, book

Hi All;
Thank You to everyone for the tremendous response..
I have the 2nd edition, with both the TTL and the Microcode versions..
I think when I first posted this, I said the 2nd Edition.. But, I could have forgotten to do that, in my excitement..
Those with the 1st Edition, and a 2nd Edition when You get Your copy, does it have the same thing for the TTL version ??
Once everyone has their copy, I hope to see some reviews of what they find, and whether they like or dislike, am satisfied or not satisfied with the book..
After thinking about it some last night after posting it, I found that I was wrong, and I most likely will need to use something else for memory, like the 2147's that are listed.. As the 2114's are 1K X 4 and the 2147's are 4K X 1.. And for my PDP 11/40 I needed the 256 X 4, and this was the closest I had for my Ram memory.. So they are set up all wrong..
I just bought what was listed as a 1980 (I hope) 1st Edition of the book.. So I can compare them..

THANK YOU Marty
 
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Hi All;
PG31, That's an idea.. "" Maybe if we all have the same book and would like to build the machine someone with the know how can design a PCB that we can all build from? ""
But, it's someone in the know of the Hardware design, first, before I would even think about the PCB..
Anyway, here are a couple of pictures of my progress..

002.jpg 001.jpg

THANK YOU Marty
 
Hi All;
g4ugm, that is exactly what I was thinking, except that with all of us making a slightly different design, we could then find and or determine what is the best circuit from all of our designs and then that would go into the final PCB Board..
Here are some more pictures..

004.jpg 003.jpg


005.jpg 006.jpg


There is still a ways to go, there is the Accumulator and shift register (74194's below the 74181's), the MA Register, Memory itself, MB Register, PC Register and IR Register and the Link Bit.. And the Front Panel (Console), then the Real FUN begins.. All of the control circuitry, which is what I need to figure out piece by piece from the Logic flows and ASM Diagrams..

THANK YOU Marty
 
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Sounds like an interesting book. I checked abebooks the other day and the copies that were $1 are now gone ;)
Another machine that had a PDP-8-like instruction set and could be built from TTL was the EDUC-8. It was serialised in an australian electronics magazine from 1974 and was just pipped at being the first published construction series of its type by the Mark-8. The EDUC-8's later articles covered building I/O such as a keyboard and I think paper tape reader.
Finding docs for it on the net seems suprisingly difficult, perhaps due to the magazine's new incarnation still selling them - possibly the compiled book form of the original serialised articles.
http://www.ljw.me.uk/educ8/
http://www.aceware.com.au/acms/ItemDetail.asp?lngItemId=68&
 
Hi All;
I finished wiring the rest of the 24 wires for the accumulator and the link bit..
I am too chilled at present to stay out here in the kitchen, so for now I will remain under the covers and try to work out the State machines.. I somewhat understand state machines..
But, my problem for now is figuring out from the flow diagrams, how to make that into the proper "or" and "and" gates.. He has some/most of the equations, and those I can translate into the proper gate sequence..
I just don't know How to describe the area of my problem..
I made some years ago a small TTL computer and it had State Sequencing logic in it and I got it to work.. I just can't find where I put the Notebook with all of my notes.. Which would help Explain and clarify some of my confusion..
Here is another picture, I know it doesn't look much different, than before..

001.jpg

THANK YOU Marty
 
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Another one enrolled in the book!

I picked mine up from Anybook Ltd. in Lincolnshire (UK). A phone call to them directly got a cheaper price than on the web (only marginally though). They said on the phone that they had a few more copies available. Beware though that all this interest in one old book may have the undesirable effect of pushing up the price for the book on the internet...

My interest is building a PDP 8/I from the microcode perspective. I found an interesting article at www.forth.com/archive/jfar/vol3/no3/article1.pdf detailing a MICROCODE simulator written in FORTH - and they used the PDP 8/I as a test case in the paper. I have found a few errors in the text - and one glaring omission with the MICROCODE (it doesn't support interrupts). Nevertheless - I will put together a Java version of a MICROCODE assembler and simulator whilst I wait for my book to be delivered...

Good find Marty - I think we have a small sub-group going here!

Dave
 
daver2 said:
Another one enrolled in the book!

I picked mine up from Anybook Ltd. in Lincolnshire (UK). A phone call to them directly got a cheaper price than on the web (only marginally though). They said on the phone that they had a few more copies available. Beware though that all this interest in one old book may have the undesirable effect of pushing up the price for the book on the internet...

My interest is building a PDP 8/I from the microcode perspective. I found an interesting article at www.forth.com/archive/jfar/vol3/no3/article1.pdf detailing a MICROCODE simulator written in FORTH - and they used the PDP 8/I as a test case in the paper. I have found a few errors in the text - and one glaring omission with the MICROCODE (it doesn't support interrupts). Nevertheless - I will put together a Java version of a MICROCODE assembler and simulator whilst I wait for my book to be delivered...

Good find Marty - I think we have a small sub-group going here!

Dave
Click to expand...

I snagged my copy from Amazon.
 
How about

Short Version:-

"Wow, Looks really interesting, will report back when I have studied"


Long Version:-

Its only just arrived today. I had a quick flip through whilst waiting for my new super steam iron to warm up. Sadly the new Iron is at full steaming capacity in 2 minutes so it was only a flip, but it looks like it will keep me going through several long dark winters, or perhaps several long beach holidays, or even the flights from the UK to VCF-East and back. I would have read more but I am already late writing my end of semester exams , and if I don't write them the students won't have anything to sit, and I will get the boot....
 
daver2 said:
My interest is building a PDP 8/I from the microcode perspective. I found an interesting article at www.forth.com/archive/jfar/vol3/no3/article1.pdf detailing a MICROCODE simulator written in FORTH - and they used the PDP 8/I as a test case in the paper. I have found a few errors in the text - and one glaring omission with the MICROCODE (it doesn't support interrupts). Nevertheless - I will put together a Java version of a MICROCODE assembler and simulator whilst I wait for my book to be delivered...
Click to expand...

Dave: Would you mind documenting your uncovered errata, here?

Others: I recently obtained copies of the laboratory materials that go with the LD12, including the wirelist (there are actually two of them, in complementary forms -- which will be helpful for cross-checking). I have them scanned, but no progress since. OCR is *completely* unsatisfactory as the originals are line printer output.

Given the significant interest on this thread, IMO we need a project site. N8VEM is a possibility as they do host various SBCs in addition to the "mainline" ECB-based boards. I'd need to make some inquiries before commandeering a folder there, and we'd need to join the applicable Yahoo! group for communications -- but might pick up some more parties/talent that way?

I also have some correspondence from a friend of Franklin Prosser (who was a student at the time that the LD12 was in-use) that may be helpful. And some photos, so-so resolution scans of the front-panel PCB front-n-back, and complete circuit diagrams of the LD12 and a series of circuit modifications for revisions starting with the LD8 and up through the LD23. (The LD30, from the 1978 book, is the one that adopted the 2910 control.)

If there is interest :)->?) I can see about getting all of these files hosted @N8VEM. Or if someone has an alternative, please speak up ...

IMO it would be very useful for the community to divide-n-conquer on translating the wirelist. Also transferring the schematics to a modern tool. Then cross-checking everything for inconsistencies ...

Thots?

-----
paul
 
Paul,

It seems as if you have come across quite a treasure trove there. I would like to see the full set of schematics, and the wire list would be useful to those of us who still wire wrap. Once I see the bill of materials, I will decide. I have a lot of 74XX TTL and perhaps enough WW sockets to have a go. My book has not arrived yet, but I assume "LD12" is the computer described in the book.

Lou
 
Hi All;
Paul, You can put me First on the list..
"" I also have some correspondence from a friend of Franklin Prosser (who was a student at the time that the LD12 was in-use) that may be helpful. And some photos, so-so resolution scans of the front-panel PCB front-n-back, and complete circuit diagrams of the LD12 and a series of circuit modifications for revisions starting with the LD8 and up through the LD23. (The LD30, from the 1978 book, is the one that adopted the 2910 control.) ""
I can't say about LD12, since the book only mentions LD20..
I also have plenty of wire-wrap sockets and Ic's and Led's..

"" If there is interest :)->?) I can see about getting all of these files hosted @N8VEM. "" What would be wrong with just keeping them here.. I have nothing against Andrew and John.. As far as a place for keeping the files and photo's, what would be so wrong about Bitsavers ??
Paul, I can scan them and put them into PDF format.. If they are 8 X 11 or there abouts..

I have the time at present to help right now !!! "" IMO it would be very useful for the community to divide-n-conquer on translating the wirelist. Also transferring the schematics to a modern tool. Then cross-checking everything for inconsistencies ... ""
Paul, can You send me a copy of the wire list, and the circuit Diagrams, just to see what kind of situation we are dealing with, so I don't insert foot into mouth.. Please !!
I think the Laboratory Manual is what You have, that is mentioned in the book.. "" C421-C422 Advanced Computer Organization Laboratory Manual ""..

THANK YOU Marty
 
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Hi All;
Here is a picture of my Universal Switch Bank, or you could call my Universal Switch Register..

001.jpg

I use this, so I don't need to or have to put big holes in my Perf Boards for switches..

Thank You, Dave G4UGM for the explanation and maybe when you have time something that will help us all..
By the way Dave, what do You Teach or are you one of students who sit ??

THANK YOU Marty
 
Hi All;

On page 331, He has a paragraph titled Register Load Signals..
For the various Registers MA(LD), MB(LD), PC(LD), IR(LD) and AC(LD)..
So for AC(LD) he has = E0.6 + E0.10 + E0.11 + E0.16 + E0.20 + E0.22 + E0.24 + E0.25 + E1.3 + E4.1 + E5.1 ..
And for IR(LD) he has = F1.2 + F3.2 + E0.5 ..
I am in the process of figuring out the rest, which He leaves for Homework.. Which I will post as soon as I get them written down..
I have the rest of them figured out, but I am not sure if the equations are to use both side of the transfers.. It isn't needed for AC(LD), but for the rest I have included both sides of a transfer.. (from-->to).. So here they are..
And for MA(LD) = E0.2 + E0.7 + E0.15 + E1.4 + F1.2 + F3.1 + F6 ..
And for MB(LD) = E0.3 + E0.9 + E0.10 + E0.11 + E0.12 + E0.13 + E0.14 + E2 ..
And for PC(LD) = E0.4 + E0.14 + E0.15 + E0.18 + E1.4 + E2.1 + E3.1 ..

Please check these out and let everyone know If You agree with what I have written up..

THANK YOU Marty
 
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