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Digital Group Z80 to 8080 Fun

Marty, the board itself would take care of the digitizing, you'd just have to get the data off of your Altair. What sort of storage do you have on the Altair? Do you have a serial interface?
 
Hi All;

Glitch, Thank You for Your Response, for Now I don't have any working storage on my Altair, it has the Altair 88-2SIo Serial Board..
It does have Altair Hard Disk Floppy Controller Card and Diskette Floppy Drive, though not very usable at present..
With John's and Andrew's Z-80 Master Card and their ZFDC Floppy Controller Card, it can have a soft sectored floppy, but at present it doesn't have an operating system..
It does have the Altair Monitor program (hex editing), used with the Serial Card, which is usable..
Using TeraTerm, the Serial card could transfer the program from the Altair to the PC, that is once It could be loaded from the Cassette tape to the Altair, via the Digital Group Cassette card..
Which would need to be interfaced to the Altair, which bring me back to gaining Your circuit from You, once you get it worked out..

THANK YOU Marty
 
Oh, excellent, I don't happen to have an 88-2SIO at the moment (sold my last one) but I do have a MITS Turnkey board which puts its console port at the same address as the first port on the 88-2SIO. I'll see what it takes to get the Digital Group tape board interfaced to the S-100 bus. I will of course share the schematic publicly. If the board isn't particularly difficult to build, I can make you one as well, or loan you mine once I've read in the tapes I have.
 
Hi All;

Glitch, OK !!

"" If the board isn't particularly difficult to build, I can make you one as well, ""
That I will decide once I see the schematic, as I have both the 32 and the 64 Character / Cassette Boards, an I/O Board and an 8080 CPU non-working Board .. I don't think I have a Digital Group Memory Board..
Which is 'why' I would prefer to go the Altair way, as I have 64K of Memory in the Altair..

THANK YOU Marty
 
Curious.. what is the advantage of copying the tapes using the original equipment vs. just dubbing or reading them into a modern PC?
 
Hi All;

Brad, The original Equipment provides the proper tones with less noise that could then be sent/copied to the PC..
Where as just copying them, You also copy any and all noise that might be inherent in either or in both tape recorders..
Therefore, when trying to read in a copy of a copy some noise could be mixed into the receiving circuit of the Digital Group Cassette Board and cause either EXTRA digits or WRONG digits to be received into the Digital Group Machine and thereby You would need to Reload the Program, and try it again..
I hope that this Helps..

THANK YOU Marty
 
Hi All;

Brad, on another note, You could make Yourself an 8080 Cassette by using Your Z-80 CPU Card and uploading the Basic Operating System, and then at Page 11 Octal, type in the 8080 Operating System from the listing, a page at a time and saving it to a New Cassette, and each time You have time to put a little more into memory, just reload what You had already saved, and continue from where You left off, until You have the full operating system saved on tape.. It wouldn't take as long as You might think it would take to put it in, That was How Digital Group did it only the other way around, where as they used the 8080 to make the Z-80 Operating System..
I have started to put the 8080 Operating System into my Hex Editor, and after it is entered I can share it with Everyone, but I don't know what good it will do anyone..

OK, here it is..
It won't Let me upload it ????
I can seem to send it thru Email, though..

THANK YOU Marty
 
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Thanks Marty.

Yes I've played around with the BIN file you sent me but haven't yet figured out how to convert it to something my 8080 can use. Octal programming sounds interesting.. if I can figure it out. :) Can you enter the entire OS at once or do you *have* to do it in chunks like you described?
 
Hi All;

Brad, Yes, I entered it and saved it and continued to enter more and save more and taking some Breaks in between.. Now, remember this was on my PC and Not my Altair, nor any Digital Group Machine..
Depending on which version of the Z-80 Digital Group Operating System, You had, would then determine how difficult or easily your entry would be..
"" Can you enter the entire OS at once or do you *have* to do it in chunks like you described? "" You can enter it all at once, if You are up to doing that..
As, far as the Bin file, You should be able to Send it with TeraTerm from Your PC, But what You would need is a Serial link on the Digital Group side and write a simple loader for the DG machine, They did have a Serial card for the DG Machine, but I don't have any of them any longer..

THANK YOU Marty
 
I might need a primer on how to program in Octal. I went into the enter an Octal Program spot on my Z80 OS tape.. and I am completely lost. I have what I believe is the 8080 Op Sys source code here (from about Page 13 of the PDF that is available at bitsavers).. so I see, like, Octal Address 001 000 -- then code -- 123. I'm assuming I want to somehow get to that address, then enter the 123 code and so on. But the octal 'programming' program only lets me enter three digits at a time... hmm..
 
Hi All;

Brad, yes the '123 is Octal, But, before that You need to get to page '011 and not page '001, You cannot write over the Z-80 Op Sys.. Otherwise You will have No OP SYS..
Let me see what the Documentation says about How to Enter a New Program, as I have forgotten, Since I used a Variant of ICOSE which asks for Your starting address and I don't think the DG OP SYS does..
"" But the octal 'programming' program only lets me enter three digits at a time... hmm.. ""
I think You Enter like '123 , then the space bar, then the next Octal Data which would be another '123 followed by the space bar and so on..
But, let me look into it..

THANK YOU Marty
 
Thanks Marty.. yeah I'm not sure if it's my keyboard.. but when I go to Octal Programming I can enter a 3 digit code which seems to take me to a memory address. And then from there I can enter 3 digits but thats it.. soon as I type the third digit it blanks the screen.. redisplays, the same registers and same data as before and that's it.

Hey one other question.. do you think it'd be a crime against posterity to have the phideck case modified to have two more holes up top for decks? I might have an opportunity to score a fourth drive... and I notice they drilled the holes in the bottom to secure four decks.. just no holes in the top.
 
Hi All;

Brad, "" but when I go to Octal Programming I can enter a 3 digit code which seems to take me to a memory address. And then from there I can enter 3 digits but thats it.. ""
OK, after You Enter the 3 digit code, then enter '011 for Your page Address, and then see if You can Enter the Octal digits, Also just for the fun of it try the Hex instead of Octal digit code..
I doubt it's Your Keyboard, maybe most likely a Cassette Read ERROR..
Also I forgot What Tapes do You have ?? You can try a different Tape as they all have the Octal and Hex Entry digits.. Just be sure You go to a page above Your Operating System and still in Read/Write Memory.. The easiest is to go to page '011..

"" Hey one other question.. do you think it'd be a crime against posterity to have the phideck case modified to have two more holes up top for decks? I might have an opportunity to score a fourth drive... and I notice they drilled the holes in the bottom to secure four decks.. just no holes in the top. ""
Yeah, the bottom was drilled for all four Decks and they Just changed out between a two hole top and a four hole top..
So, No big deal whether You change it or they changed it from a two hole to a four hole top..


THANK YOU Marty
 
Thanks Marty. I'd want to find a professional to cut it correctly. I'm digging around too to see if I can find a source for replacement covers.

I'm not sure if I have the gumption to go for a 4 drive setup. I'm not clear if that requires two separate controller cards or what.. I'm reading the documentation now but some of it is kind of over my head. :) I've decided to do the setup more or less as originally specified. I know that will produce reliability issues, however from a historical standpoint I think that's the best way to stay true to the intent. Not like I'll be using this thing seriously anyway.
 
Hi All;

Brad, "" I'm not clear if that requires two separate controller cards or what.. ""
No, One Phi-Deck card can control up to Four Phi-Decks,
more than four phi-Decks takes another Card..

"" I've decided to do the setup more or less as originally specified. I know that will produce reliability issues, however from a historical standpoint I think that's the best way to stay true to the intent. ""
The Biggest problem is Noise to and from the Heads, With Satellites and Cell Phones, interfering with the Signal..
You might Not ever be able to get it to work reliably, Unless the Phi-deck Card is mounted in the Phi-Deck case, like Bryan did, and even that may need some more pre-amps and further filtering to the signal before You can get it to work..

Brad, go to http://bitsavers.informatik.uni-stuttgart.de/pdf/digitalGroup/software/Suding_Operating_System.pdf for information on Using the Operating System, Stuff that I didn't even know/remember..

THANK YOU Marty
 
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Hi All;

Falter, No and Yes.. So, One Motor has Triple I marker on it, which is the Parent Company for Phi-Deck..
I can't tell for sure, but, it either is a ReBranded PhiDeck or a Knock-off copy of a PhiDeck..
So, If You thought it would be worth the price, You could/might be able to use it for Parts for what You already have..
If I were You, I would just stick with having the two drives and the Enclosure, and work on getting those two units working, before wanting to make it into a four hole drive System, which would be just as un-usable if You cant get a two hole system working..
But, for looks if You really want a four hole drive system, then it would probable be OK..
The Motors are 5 Volt, but, I can't say what speed the drive is set up for..

Brad, If You decide to get it, and He Doesn't want to Send it to You up their in Canada, Just Give Him My Address and I will ReSend it to You..

THANK YOU Marty
 
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Hi All;

Glitch, have You had the Time to do any work on the Altair (S-100) to Digital Group Conversion ??
I have my Dg MotherBoard out, and have it Powered up, I have to program an Eprom for it (2716), with my conversion Board from 1702 to 2716..
And attach the TV Output and the Cassette input and Output wires.. I don't have a Keyboard for it any more, But, I can get everything else on a working basis..

THANK YOU Marty
 
Marty said:
Glitch, have You had the Time to do any work on the Altair (S-100) to Digital Group Conversion ??
Click to expand...

I haven't had time to actually build any hardware yet, but looking at the documentation for the display/cassette board, it looks like really it's just some active filters and signal conditioning, and all of the tape de-serialization is done in software. I'm thinking it would be pretty easy to build the DG filter/conditioning circuit on a S-100 protoboard or a bit of perfboard and either write a routine for 8080/Z80 or use it with a microcontroller. I thought there was more to the DG board than just "is the current audio input a zero, or a one?" but that appears to be it. The output goes into a single bit of the parallel I/O port board, so making a S-100 -> DG display/cassette board adapter wouldn't save much work over just recreating the DG tape circuit.
 
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