For a vintage computer project, which processor is easier to use?

[colorado.rob]

Vintage to me is anything that was built before you were born or maybe existed when you were a young child.  If the OP is in their 20s, vintage isn't that long ago.

If you're doing "vintage", why not do something interesting like a PDP-11?

https://opencores.org/project,w11

[rstofer]

Vintage to me is anything that was built before you were born or maybe existed when you were a young child.  If the OP is in their 20s, vintage isn't that long ago.

If you're doing "vintage", why not do something interesting like a PDP-11?

https://opencores.org/project,w11

But I predate the Eniac!

ETA:

That PDP-11 project seems like fun.  I have the Digilent board...
The ONLY thing that makes these projects worth the effort is if there is software to run.  In the PDP-11 case Unix V5 runs.  You can't expect better than that!

The IBM1130 software is available and it's pretty easy to build a system using the information provided in the Functional Characteristics manual.  It won't be cycle accurate but it will run at 50 MHz whereas the original that I used ran at 400 kHz.  Pretty good speedup.

http://ibm1130.org/

Way back in '70, this was the first computer I ever used or even saw!  It helped immensely getting through undergrad using the IBM Electronic Circuit Analysis Program (similar to LTspice but with punched cards and no built-in components).  For school work, it was all about the plotter.  There's nothing like an accurate Bode' Plot to attach to homework.

I still use my FPGA implementation whenever I feel the need for Fortran IV and a plotter!

[colorado.rob]

But I predate the Eniac!

https://en.wikipedia.org/wiki/Jacquard_loom
 

[NivagSwerdna]

It's pretty tough to stop this thread from oscillating when the original topic seemed to be 'vintage' and then Berkeley Sockets comes up.

I think you will find this thread was 100% socket free until you mentioned it?

https://www.eevblog.com/forum/microcontrollers/converting-struct-in-to-array-changing-byte-order/msg1248367/#msg1248367

[rstofer]

It's pretty tough to stop this thread from oscillating when the original topic seemed to be 'vintage' and then Berkeley Sockets comes up.

I think you will find this thread was 100% socket free until you mentioned it?

Reply #40:

https://www.eevblog.com/forum/microcontrollers/for-a-vintage-computer-project-which-processor-is-easier-to-use/msg1253379/#msg1253379


True, it was tangential to my describing the eZ80F91 CP/M project...

I'm starting to like that PDP-11/70 project...

[NivagSwerdna]

I'm starting to like that PDP-11/70 project...

Now you are talking.  Just need to add a VT100 with smooth scroll turned on. Software wise you just need DECUS Adventure and for fun TECO.

[Bruce Abbott]

The introduction of the IBM PC in 1980 pretty much wiped out the idea of 'personal computing' and started 'just commercial computing'.  Anybody could run an IBM PC

Anything from the 1980's is now 'vintage'.

When the IBM PC was released in 1980 it had a keyboard, 64k RAM, and a tape interface. Everything else was an option. You could have one or two 360k floppy drives, but the only graphics card available was monochrome text. Compared to other 'personal' computers of the day it sucked, but it had one sure-fire selling point - the letters I B M.

The other reason the PC became so popular is that it was incredibly easy to reproduce. Clone manufacturers quickly switched from making Apples to PCs, which they were able to sell for half the price of a real IBM. Since almost everything was an option, 3rd party manufacturers had an enormous potential market to exploit. But it wasn't until the 1990's that it took over from 'personal' computers, because until then it really was just a 'business' machine.
 
I think the main reason old PCs are often not considered 'vintage' is that a modern PC can still (for the most part) run the same software. And the early IBM wasn't really a computer anyway - it was little more than a motherboard with CPU and RAM, stuffed full of 3rd party cards. With so many upgrade options and the continually advancing specifications, there isn't any point at which can you say this PC is vintage, but that one isn't.

It also doesn't help that so many of them are still around. I have 5 working PCs of various vintage, a few more that just need a new power supply or hard drive, 4 laptops, and a cupboard full of parts. Time for a cull!

[rstofer]

I walked past a PDP-11 one time and that's as close as I ever got.  Been in the same room with a couple of Vaxen...

I'm just not a PDP-11 guy but since I already have the board(s), it might be fun to install the Xilinx toolchain under Debian Linux and see how it works out.  I rather like the author's idea of using a peripheral server under Linux.  I could see converting my IBM1130 to do the same thing.

I don't have the Nexys3 board which will give much faster USB transfers and also has more onboard SRAM but if I can get the system running on a Spartan 3 Starter Board, I will know if I like it enough to part with $270 on an obsolete board (if they still have them).

[rstofer]

The introduction of the IBM PC in 1980 pretty much wiped out the idea of 'personal computing' and started 'just commercial computing'.  Anybody could run an IBM PC

Anything from the 1980's is now 'vintage'.

See, I wouldn't consider an IBM PC (beyond, maybe, the original) to be "vintage".  By the time IBM got in the business, there were dozens of S-100 machine types already running (Altair, CompuPro, Cromemco, etc).  The 8080 machines had UCSD Pascal two years before the IBM PC was introduced and this finally allowed these machines to do useful business computation.

Furthermore, current machines are simply evolutionary, not revolutionary.  The Altair 8800 was revolutionary and I suppose the Apple II fits that concept as well.  Perhaps even the Commodore Pet...  Maybe, if I was pushed, I would include the original IBM PC because it introduced a new bus structure that was a vast improvement over S-100.  But nothing beyond that...

I still think the PC-AT keyboard is the best keyboard ever invented.

[Elf]

It's pretty tough to stop this thread from oscillating when the original topic seemed to be 'vintage' and then Berkeley Sockets comes up.

Wow, I did not realize that offhandedly mentioning the socket library was so disruptive. BSD sockets came out in 1983 with 4.2BSD by the way. As in, run on systems like the VAX 11/780, of similar vintage to the PDPs you are discussing. I never had a PC older than an Apple ][e, but I do still have (and use) a lot of old UNIX systems like VAX, Alpha, various generations of Sun, SGI, etc. The concept of networking came around a lot earlier for multiuser systems than it did for personal computers.

As you point out, vintage has a lot of personal meaning. I'm sure to a lot of people even a Pentium II with a 56k modem is "vintage" now. It is pretty hard to decide the dividing line between what is vintage and what is not, since so many things that were created in the 70s-90s are still in use, virtually unchanged. I think of vintage as anything on display on the 2nd floor of the Living Computer Museum, which by the way is worth a visit, unless mentioning this is also too off topic and is going to send someone into a tizzy.

As far as these projects go, I generally just think of it as trying to construct your own computer around an older architecture (e.g. 68k, 6502, Z80, et. al.). Some people want to recreate the functionality of an entire original machine, some people want to use an original ceramic chip and discrete logic with a rat's nest of breadboard wires, some people (like me) just want to use the old CPU and the rest can go. I have a 6502 game system project queued up where I want to use a modern FPGA as an MMU to do paged memory, use either an FPGA or a DSP for a tiling and sprite engine, have coprocessors for USB mass storage, and output to HDMI at 720p. I enjoy the mix of old and new. I don't feel the need to go back to cassette tape program storage or to try and faithfully rebuild an 8" floppy drive, but I can still enjoy writing the "controlling software" in 6502 assembly, having to be creative with use of memory and cycles.

For technix, the original poster, it looks like he already has some older chips on hand that he wants to find a use for but also wants to incorporate modern components; e.g. the mention of USB OTG and Ethernet.

[colorado.rob]

If you want to do something legacy from the 80's, how about a Cray?  I mean, those things just *looked* cool.

http://www.chrisfenton.com/homebrew-cray-1a/

[NivagSwerdna]

The other reason the PC became so popular is that it was incredibly easy to reproduce.

In my first job after university I worked for a company that amongst other things developed (token ring) network cards for PCs... our design was coming along nicely and then IBM moved to the IBM PS/2 and patented/licenced the new card bus (MCA).... we received our first real PS/2 and within minutes of arriving we had completely dissembled it... to our dismay it didn't work when we reassembled it.... didn't like the battery backup being removed or something like that.  But it wasn't long before either the bus was licenced or legally challenged... can't remember the details.  This thread is making me feel very old!

[rstofer]

There is also a Computer History Museum in Mountain View (Silicon Valley) that is well worth the trip.

[technix]

For me the vintage part is the CPU core complex design and maybe some code (if the hardware is built to spec with some existing standards like IBM PC XT.) I am fully okay with using modern parts for peripherals and system bus (the Intel EPM7128 CPLD system bus controller, WCH CH375 USB OTG controller, and WCH CH395 Ethernet controller.) And I am born in 1993 so anything in the 80s are vintage to me, not just the original IBM PC XT (or AT)

[colorado.rob]

How many of you geezers feel old now?!? 

[technix]

How many of you geezers feel old now?!? 

For my experiment environment it is almost entirely legacy free (No PS/2, no VGA, no RS232) so I cannot even use true vintage designs (or I won’t be able to even write the disks for or communicate with the old machine from my usual workstation.)

I cannot even reuse the display of my computer with the adapter chips as there is no way a vintage computer can drive a 4K 2160p60 monitor.

[cdev]

The number one thing I remember from that era was that the older x86 family of chips had an unbelievable number of workarounds for this or that that needed to be incorporated into code (and of course the tools that exist today were absent)

the kludges made the early intel x86 platform quite painful to use compared to say the motorola 68000.

[NorthGuy]

For my experiment environment it is almost entirely legacy free (No PS/2, no VGA, no RS232) so I cannot even use true vintage designs (or I won’t be able to even write the disks for or communicate with the old machine from my usual workstation.)

I cannot even reuse the display of my computer with the adapter chips as there is no way a vintage computer can drive a 4K 2160p60 monitor.

Why vintage? Wouldn't it better to design your own?

[rstofer]

The number one thing I remember from that era was that the older x86 family of chips had an unbelievable number of workarounds for this or that that needed to be incorporated into code (and of course the tools that exist today were absent)

the kludges made the early intel x86 platform quite painful to use compared to say the motorola 68000.

Maybe have the video come out as R-G-B and use a TV set for a display.  Are you sure your monitor doesn't have VESA VGA capabilities?  There are a number of monitors around that can handle VGA or Composite Video.  I have a little 7" monitor from AdaFruit that might be workable:
https://www.adafruit.com/product/1667

5-1/4" floppies are kind of a PITA.  It is dead simple to add a Compact Flash disk to just about any bus oriented system.  If you have a disk image, you can use the Linux dd command to write the image.  If you want to create 16 drives like I did for the Z80 system, you can write some code to build empty drive images in a large file, copy in the real image for the first drive and then write the entire file to the Compact Flash with one command.  Somehow I got the CP/M image plus Kermit loaded on the first drive and I transferred everything else from the 8" floppies on my CompuPro Z80 machine.

[Nusa]

How many of you geezers feel old now?!? 

For my experiment environment it is almost entirely legacy free (No PS/2, no VGA, no RS232) so I cannot even use true vintage designs (or I won’t be able to even write the disks for or communicate with the old machine from my usual workstation.)

I cannot even reuse the display of my computer with the adapter chips as there is no way a vintage computer can drive a 4K 2160p60 monitor.

I don't feel like a geezer yet, but I am getting up there. I've experienced most of these CPU's the first time around as a Computer Science student and professional, so I don't feel any great urge to recreate them myself.

PS/2 and VGA didn't exist in the vintage era you're trying to replicate, so why would you need them now? RS232 was, and it's easily adapted to USB with a cheap adapter cable. Which means you can use any modern computer as a serial terminal, which includes most smartphones. If you want emulations of VT100 terminals or the like, those exist. In any case, that gives you the sort of interface you ACTUALLY HAD back in the day. (Well, it might have been an even older paper terminal TTY with paper tape reader/writer setup, but unless you actually own that antique you can forget that.)

If you're truly vintage, all the computer itself will have is idiot lights, toggle switches, and UART or RS232 port. Part of the experience, if you aren't old enough to have lived it, is being able to stop the computer clock, single-step programs, and modify memory locations using nothing but the lights and toggle switchs on the computer panel.

[technix]

How many of you geezers feel old now?!? 

For my experiment environment it is almost entirely legacy free (No PS/2, no VGA, no RS232) so I cannot even use true vintage designs (or I won’t be able to even write the disks for or communicate with the old machine from my usual workstation.)

I cannot even reuse the display of my computer with the adapter chips as there is no way a vintage computer can drive a 4K 2160p60 monitor.

I don't feel like a geezer yet, but I am getting up there. I've experienced most of these CPU's the first time around as a Computer Science student and professional, so I don't feel any great urge to recreate them myself.

PS/2 and VGA didn't exist in the vintage era you're trying to replicate, so why would you need them now? RS232 was, and it's easily adapted to USB with a cheap adapter cable. Which means you can use any modern computer as a serial terminal, which includes most smartphones. If you want emulations of VT100 terminals or the like, those exist. In any case, that gives you the sort of interface you ACTUALLY HAD back in the day. (Well, it might have been an even older paper terminal TTY with paper tape reader/writer setup, but unless you actually own that antique you can forget that.)

If you're truly vintage, all the computer itself will have is idiot lights, toggle switches, and UART or RS232 port. Part of the experience, if you aren't old enough to have lived it, is being able to stop the computer clock, single-step programs, and modify memory locations using nothing but the lights and toggle switchs on the computer panel.

To me PS/2 and VGA are already vintage - in contrast my home workstation is built around USB and DisplayPort for peripherals and display, and a further upgrade to Thunderbolt 3 is planned. I know that RS232 can be easily adapted (and for homebrew boards I would just build the USB to TTL UART chip right in there.)

For me since there is a CPLD with JTAG boundary scanning in the system bus and generates the processor clock, I can skip the toggle switches and idiot lights and use the boundary scan features of the CPLD as a makeshift JTAG debugger.

[Muxr]

I always found 6502/6510 to be pretty easy, in fact in college they used 6502 to teach us assembly. I was doing x86 assembly by that point.

[technix]

Quote

is static CMOS so there is no minimum clock rate.

This is also true of the current CMOS Z80 chips (Z84c00) (and I think of a lot of the more recent CMOS versions of most "classic" chips, like the 80c88 you can get from Intersil (sticker shock!), the 80c18x (might be an interesting choice; has some built-in features that make systems easier to build, but will still run MSDOS), etc)

I found some 80286 and 80287 though. Are those any good?

And I also found someone selling Am486DX4-75 in QFP package...

[technix]

I always found 6502/6510 to be pretty easy, in fact in college they used 6502 to teach us assembly. I was doing x86 assembly by that point.

My school had 8086 real mode assembly and later ARM9.

Is ARM9 anywhere near vintage?

[Muxr]

I always found 6502/6510 to be pretty easy, in fact in college they used 6502 to teach us assembly. I was doing x86 assembly by that point.

My school had 8086 real mode assembly and later ARM9.

Is ARM9 anywhere near vintage?

it's decently old I suppose but it's a far cry from the simplicity of the 8bit CPUs from the 80s.