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rpdom
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Re: Is it possible to upgrade RAM for the raspi?

Fri Feb 19, 2016 9:10 pm

asandford wrote:
rpdom wrote:
morphy_richards wrote:Wow.wouldnt it be an interesting challenge to get Linux running on a BBC Micro.
I'm pretty certain a vesion of Unix was available for the BBC Micro with at least one of the various experimental co-processors. I'm sure I saw one being tried out. There was also RiscIx (sp?) for an early ARM at some point too.
I thought the 32016 used some sort of unix, but apparently it didn't.

Also AVRs are (arguably) more powerful than a 6502, and it took 2 hours to boot on a 16MHz AVR, so how long on a 1MHz 6502?
The 6502 Copro ran a bit faster than that, but I was thinking about the ARM1 which (IIRC) ran at 3MHz (I had a couple of them at one point - cheap at only four grand each for the 4MB versions, and no, I didn't buy them). I thought there was a Unix for the 32016 though. I did have a poke at one of those once.

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Re: Is it possible to upgrade RAM for the raspi?

Fri Feb 19, 2016 9:24 pm

rpdom wrote: The 6502 Copro ran a bit faster than that, but I was thinking about the ARM1 which (IIRC) ran at 3MHz (I had a couple of them at one point - cheap at only four grand each for the 4MB versions, and no, I didn't buy them). I thought there was a Unix for the 32016 though. I did have a poke at one of those once.
Yes, I'm sure the 32016 ran a unix of some sort, but it was a long time ago (and I was at school and didn't have access to such things). I'm sure the Pi could be interfaced to the Tube, or even the 1Mhz bus, but for what use I'm not sure (Elite with GPU acceleration?)

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Re: Is it possible to upgrade RAM for the raspi?

Fri Feb 19, 2016 10:11 pm

Torch Computers packaged the BBC micro as a front end for either a Z80 (running CPN, later called MCP -- a ROM-based CP/M, IIRC) or, more interestingly, a 68000 which was my introduction to Unix. I only borrowed it for a few days -- didn't get much beyond the character-based Star Trek! No X server in those days, this was before Windows was around in any significant way.
Both these (certainly the Z80, which I still have) interfaced via the Tube.
asandford wrote: Also AVRs are (arguably) more powerful than a 6502, and it took 2 hours to boot on a 16MHz AVR, so how long on a 1MHz 6502?
The BBC Micro had a switchable clock -- 2MHz for running code and ROM/RAM access, 1MHz for I/O (except IIRC the Tube, which was 2MHz). This was the "good old days" when everything (memory and peripherals) was accessed through a 16-bit address bus. The Beeb did have memory bank switching for the application ROM, to allow BASIC, DFS, NFS, and others to exist in the "same" 16K memory space.

Relevant to an ongoing Pi discussion -- both my Beebs had a fan added!

EDIT: On further thought, in the interests of historical accuracy, MCP was the 6502-side code, for disk access and maybe other I/O, while the Z80 CPN code was actually disk based -- either floppy or even 5/10/20MB hard disk. The Z80 had some bootstrap code in ROM, I don't remember having many issues with that. (My job included repairing Beebs and that generation of personal computing equipment.)
Last edited by davidcoton on Fri Feb 19, 2016 10:59 pm, edited 1 time in total.
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Re: Is it possible to upgrade RAM for the raspi?

Fri Feb 19, 2016 10:27 pm

davidcoton wrote:Relevant to an ongoing Pi discussion -- both my Beebs had a fan added!
So did mine! The cobbled-together Model B I owned for a number of years was built from the repaired remains of an original machine that had suffered the all-too-common exploding switch-mode PSU problem. I replaced the blown up chips and repaired the vapourised PCB tracks on the mainboard and then built a nice chunky analogue PSU for it as I didn't want it suffering the same fate again. The TO3-canned 2N3055 that was regulating the 5V rail did get rather toasty, so not having a fan wasn't a sensible option. :lol:
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Re: Is it possible to upgrade RAM for the raspi?

Fri Feb 19, 2016 10:40 pm

davidcoton wrote:
asandford wrote: Also AVRs are (arguably) more powerful than a 6502, and it took 2 hours to boot on a 16MHz AVR, so how long on a 1MHz 6502?
The BBC Micro had a switchable clock -- 2MHz for running code and ROM/RAM access, 1MHz for I/O (except IIRC the Tube, which was 2MHz). This was the "good old days" when everything (memory and peripherals) was accessed through a 16-bit address bus. The Beeb did have memory bank switching for the application ROM, to allow BASIC, DFS, NFS, and others to exist in the "same" 16K memory space.

Relevant to an ongoing Pi discussion -- both my Beebs had a fan added!
OK, it was 2MHz, was a long time ago (got my beeb when I was ~16).

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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 12:05 am

asandford wrote:
rpdom wrote:
morphy_richards wrote:Wow.wouldnt it be an interesting challenge to get Linux running on a BBC Micro.
I'm pretty certain a vesion of Unix was available for the BBC Micro with at least one of the various experimental co-processors. I'm sure I saw one being tried out. There was also RiscIx (sp?) for an early ARM at some point too.
I thought the 32016 used some sort of unix, but apparently it didn't.

Also AVRs are (arguably) more powerful than a 6502, and it took 2 hours to boot on a 16MHz AVR, so how long on a 1MHz 6502?
2 hours to boot Ubuntu graphical desktop ( unless I read it wrong* (damn just almost walked into a telegraph pole, who put that there))what about if we just load a command shell and add access to more memory through the tube.
* I did read it wrong

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rpdom
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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 7:32 am

asandford wrote:Yes, I'm sure the 32016 ran a unix of some sort, but it was a long time ago (and I was at school and didn't have access to such things). I'm sure the Pi could be interfaced to the Tube, or even the 1Mhz bus, but for what use I'm not sure (Elite with GPU acceleration?)
At least one third party ARM CoPro has been created. I think it used an ARM5, or it could have been later. It runs at some silly speed compared to the original Copros, but the interface will be limited to 2MHz or less.

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rpdom
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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 7:35 am

davidcoton wrote:Torch Computers packaged the BBC micro as a front end for either a Z80 (running CPN, later called MCP -- a ROM-based CP/M, IIRC)
I remember the Torch Z80 unit. It sat on top of the Beeb with twin floppy drives. I played around with one I found at work for a while, then we got bored and disconnected it so we could play Chuckie Egg on the Beeb on night shifts :-)

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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 3:36 pm

mikronauts wrote:Step 1: Build an inter-dimensional alternate time line travel device
Step 2: Locate alternate timeline where it is possible to extend the ram
Step 3: Travel to alternate time line

*1,2,3 are left as an exercise for the reader
stderr wrote:
W. H. Heydt wrote:Not only can you not increase the RAM on the Pi2B, but even if you could add RAM, the BCM2836 SoC can't address any more than it already has.
But what if you just don't care about it being impossible, how would you do it anyway?
BEST
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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 4:43 pm

Problem is, as far as I can tell, everytime somebody manages to build an inter-dimensional alternate time line travel device we never see or hear from them again!

I'm expecting mikronauts to disappear from this reality any time now.
Memory in C++ is a leaky abstraction .

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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 4:47 pm

Heater wrote:Problem is, as far as I can tell, everytime somebody manages to build an inter-dimensional alternate time line travel device we never see or hear from them again!
So that's where most of the unicorns went!
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Re: Is it possible to upgrade RAM for the raspi?

Sat Feb 20, 2016 10:09 pm

rpdom wrote: At least one third party ARM CoPro has been created. I think it used an ARM5, or it could have been later. It runs at some silly speed compared to the original Copros, but the interface will be limited to 2MHz or less.
Hmm, well there was the Computer Concepts ARM card for PCs many years ago. I had a couple to run the RISC OS Smalltalk on. Eventually gave them back to Charles Moir when he had a need for just a couple more for some project and didn't want to have to restart production.

I had (actually still have but I doubt it works) an original Acorn "silver fox" prototype that had an ARM 1 until it got upgraded to an ARM 3 turbo configuration. I think it's numbered 8 or something. I used that thing for years. Even welded a carry handle on the case to make easier to carry as handbagge for flying to the US. Don't think it would led get past security anymore!
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Re: Is it possible to upgrade RAM for the raspi?

Sun Feb 21, 2016 1:37 pm

Heater wrote: When I wanted compile the Qt5 libs on the Pi it would not build without more memory space. I set up an NFS share to my PC and pointed the swap at that. The file space on the PC was memory mapped so the Pi ended up using the RAM of my PC for it's virtual RAM!
limited by latency and bandwidth of the usb/ethernet link though :)

There were real RAM disks made by acard & gigabyte which were a load of RAM DIMMS with a SATA interface,
was super low latency and beat SSDs
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Re: Is it possible to upgrade RAM for the raspi?

Sun Feb 21, 2016 1:54 pm

Yeah, sometimes working with the Pi is like painting a room with a long thin brush poked through the keyhole in the closed door.
Memory in C++ is a leaky abstraction .

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Re: Is it possible to upgrade RAM for the raspi?

Sun Feb 21, 2016 1:56 pm

There's an ARM7 Tube Co-pro for the BBC Micro detailed here : http://sprow.co.uk/bbc/armcopro.htm

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Re: Is it possible to upgrade RAM for the raspi?

Sun Feb 21, 2016 2:32 pm

morphy_richards wrote: 2 hours to boot Ubuntu graphical desktop ( unless I read it wrong* (damn just almost walked into a telegraph pole, who put that there))what about if we just load a command shell and add access to more memory through the tube.
* I did read it wrong
About 4 hours (watching the video) to full sysvinit running - should have used systemd, as it's much faster :lol:

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rpdom
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Re: Is it possible to upgrade RAM for the raspi?

Sun Feb 21, 2016 4:08 pm

noggin wrote:There's an ARM7 Tube Co-pro for the BBC Micro detailed here : http://sprow.co.uk/bbc/armcopro.htm
Ah yes, Sprow's one. That's the board I was thinking of :)

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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 8:34 am

rpdom wrote:
morphy_richards wrote:Wow.wouldnt it be an interesting challenge to get Linux running on a BBC Micro.
I'm pretty certain a vesion of Unix was available for the BBC Micro with at least one of the various experimental co-processors. I'm sure I saw one being tried out. There was also RiscIx (sp?) for an early ARM at some point too.
Wasnt there Posix on the Amiga?
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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 8:43 am

rpdom wrote:. I thought there was a Unix for the 32016 though. I did have a poke at one of those once.
Pity NatSemi never managed to make a reliable 32016 (or 32032). The Whitechappel MG1s we had at university were horribly unreliable :-(
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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 7:40 pm

PeterO wrote:
rpdom wrote:. I thought there was a Unix for the 32016 though. I did have a poke at one of those once.
Pity NatSemi never managed to make a reliable 32016 (or 32032). The Whitechappel MG1s we had at university were horribly unreliable :-(
PeterO
And what happened to Inmos' Transputer - dissapeared without a trace?

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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 7:49 pm

See http://www.xmos.com/ for the Transputer's descendant, positioned as a microcontroller.
asandford wrote:And what happened to Inmos' Transputer - dissapeared without a trace?
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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 10:32 pm

mikronauts wrote:See http://www.xmos.com/ for the Transputer's descendant, positioned as a microcontroller.
Interesting, thanks.

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Re: Is it possible to upgrade RAM for the raspi?

Mon Feb 22, 2016 10:54 pm

asandford
And what happened to Inmos' Transputer - dissapeared without a trace?
The whole Transputer concept was based on the idea of Communicating Sequential Processes (CSP) as outlined by Tony Hoare in 1978. https://en.wikipedia.org/wiki/Communica ... _processes

As it turned out the world was not ready for that. Especially the Occam language that went with it. People would rather have C at the time.

End of Inmos.

But the CSP idea lives on. People like Google have a problem in programming thousands of interconnected compute nodes to achieve some task. So they devise a language like Go that does all that stuff Tony Hoare described in 1978.

With the fall of Moore's Law we have to find ways to get computing done efficiently and CSP is one way.

Of course the XMOS chips are a recreation of the hardware approach to all this.

What is old is new again. Nearly forty years later.
Memory in C++ is a leaky abstraction .

xLetumx
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Re: Is it possible to upgrade RAM for the raspi?

Fri Apr 21, 2017 12:41 pm

Old post...but you could upgrade the RAM. If you replace several chips and write your own software for the reverse-engineered board

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Re: Is it possible to upgrade RAM for the raspi?

Fri Apr 21, 2017 4:29 pm

xLetumx wrote: ... replace several chips ...
Which chips in particular?

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