a question that came up the other evening

[tater1337]

as time marches on, so does technology, and the question for today is.......

how does the picaxe compare in power to personal computers of yesteryear?

I mean, the 08M certainly must be a bit more beefier than say the 4004 chip that ran old homebrew computers(altair and such) and then we have the 8008, then the 8080, 8088, NEC v20, V30, 8086, 80386,80486.........

just what were the brains on the mercury, gemini, and apollo spacecraft? how would picaxes compare to them?

 

[BeanieBots]

I wouldn't want to try and compare purely on a "power" level because I don't really know what that even means in a litteral sense.
What is worth noting however, is all the extras you get on something like the raw PICs which make up PICAXE.

For example, those other micros have ZERO memory until you add some with external chips. You would also need some decoding to address it and different types depending on if it was to hold program or user memory.
If you wanted serial comms, that would require another (often 40 pin) chip, likewise if you wanted a counter/timer.
About a dozen chips to get something close to a 28X1.
Then again, they have the ability to directly address much more memory and/or peripheral devices and did it parallel rather than serial so like for like speed was/is much quicker. These points make it hard to compare because it's not like for like. In general, I'd say they have more processing capability than PICAXE but not in anything remotely close to the same level of ease.

 

[MartinM57]

Agree.

PICAXEs are microcontrollers, which generally means they have resonably powerful processing power, memory (of various types), counters, timers, serial/bus-oriented comms, brown out detectors, clocks etc etc onboard within a single ceramic multi-pin package

The other numbers you quote are generally regarded as microprocessors, which (although obviously getting pretty pwerful processing power in something like an 80486) tend to need external devices (memory, crystals/resonators, address decoders etc etc) to allow you to do something useful with them.

The spacecraft computers of the age you mention were even more basic, comprising separate hardware elements (ALU, address decoders etc) in discrete logic chips with program code being held on wire matrices with ferrite beads at appropriate intersections to define what the "software" actually did (and made by little old ladies with good knitting skills - honest)

 

[moxhamj]

I mean, the 08M certainly must be a bit more beefier than say the 4004 chip that ran old homebrew computers(altair and such) and then we have the 8008, then the 8080, 8088, NEC v20, V30, 8086, 80386,80486.........

just what were the brains on the mercury, gemini, and apollo spacecraft? how would picaxes compare to them?


Well, I'm glad you asked.

You can try out the Gemini and Apollo computers here http://www.ibiblio.org/apollo/

It makes you look at the Apollo 13 movie in a new light. Here you are, hurtling vaguely towards earth and if you don't program this computer right you either slam straight into the earth, or miss completely and head off into space. You have 1 hour...

Re older machines, older computers like the 8080/Z80 have a lot more memory (see the MBASIC signon below with 30k free). And you can save big text files (hundreds of k) and read them back. And have multiple programs you can load and run in turn. And they can write and compile programs on themselves. http://smarthome.viviti.com/build

But in terms of pure speed, let's give it a try. We know the picaxe executes about 1000 instructions a second in Basic. So a loop 10,000 times would be about 10 seconds on a picaxe. Lets try that in MBASIC on a Z80 running at 3.6Mhz:

A>MBASIC

BASIC-80 Rev. 5.21
[CP/M Version]
Copyright 1977-1981 (C) by Microsoft
Created: 28-Jul-81
30776 Bytes free
Ok
10 FOR A%=1 TO 10000
20 NEXT A%
Ok
run
Ok

Time to run was about 9.5 seconds.

So, the answer is, almost exactly the same as a picaxe 08M!

We can cheat a bit though on the Z80, and change from 'interpreted' mbasic to a compiled program:

list
10 FOR A%=1 TO 10000
20 NEXT A%
Ok
run
Ok
save "SPEED",A
Ok
SYSTEM
CP/M V2.2C
A>SUPERSUB BAS SPEED

SuperSUB V1.1
CP/M V2.2C
A>BASCOM =SPEED /E

00000 Fatal Error(s)
23034 Bytes Free
CP/M V2.2C
A>L80 SPEED,SPEED/N/E

Link-80  3.44  09-Dec-81  Copyright (c) 1981 Microsoft

Data    4000    41A3    <  419>

39171 Bytes Free
[4013   41A3       65]
CP/M V2.2C
A>SPEED


CP/M V2.2C
A>

Now it takes about 1.5 seconds.

Anyway, how are you going preventing your spacecraft from missing the earth and spiralling into the sun? *grin*

 

[westaust55]

Not exactly a “power” comparison but some thoughts on a similar vein.
(Nostalgia time)

My first home brew computer (mid 1970’s) was based on the national Semiconductor SC/MP chip. 256 bytes of memory, no ROM, clock speed 1MHz (from memory), all programming in machine code, input via 8 toggle switches and output via 8 LED’s. No BASIC available

Next (late 1970’s) was a home brew Motorola 6800 based home brew with 1MHz clock speed, started with 512 bytes RAM built up to 8.5Kbytes of RAM, initially 1 or 2Kbytes ROM which was expanded by a few Kbytes of EPROM, initially hex keypad with some 7-seg displays for IO which I later upgraded to ASCII keyboard (built from a kit) and using a TV video board and ex TV station 8 inch (200mm) green screen monitor. Integer only BASIC (took 4K of RAM) with around 26 variables (a to z). Programs stored on cassette tapes. Added RS232 for dot matrix printer (heck I even modified the printer to have 4 times the RAM, extra characters etc)

Third machine (1980) started life as an OSI C2-4P using MOS Technology 6502 cpu, clock speed 1MHz, started with 8k RAM and built own board to have 24 kbytes RAM, started with 9kbytes Rom which I changed to 20kbytes EPROM, on board video card with 32 lines and 64 chars per line and 16 colours – I hacked and added twice the characters, flashing and inverted characters, BASIC interpreter (floating point numbers and around 260 variables from memory). BASIC interpreter was hacked for 256 x 256 “chunky” graphics, and text to speech (added SAY keyword), extra added IO for program cartridges, etc.



From this and knowing the IO I had on each , around the late 1970’s, the home brew computers had the same “capabilities” as a PICAXE chip but needed a box the size of a PC case compared to now where the capabilities being packaged in an 8 thru 40 pin chip and with a keypad and LCD display all still can fit in a box the size of a desktop PC power supply.

 

[manuka]

Great nostalgia guys. Thank goodness the screens haven't been miniaturised as well. I now find anything less that a decent 19" LCD a pain -& my vision is good! But displays- what kind of talk is this? How about pre screen computing!?

My first programmable device (1975) was a summer LOANED (they then cost ~a weeks income) 49 program step handheld HP-25 with red LEDs. I well recall the disbelief of workmates when I did more in a few hours with it than in days that the then normal punched card approach would have taken.

The HP25 attribute I recall most keenly relates to its immediate operator feedback. Magical! It's hard for you young whipper snappers to credit I guess, but punch card batch programming often then took painful hours to debug or batch run- perhaps at a computer centre clear across town. No wonder young Bill Gates pondered alternatives...

 

[Dippy]

Oh heck! Stan losing his eyesight?
Obviously spent too much time fiddling with his Colossus when he was a schoolboy

 

[hippy]

It's easy to say, "more powerful than the computer which put a man on the moon", as we frequently do hear bandied about, but much harder to prove it is so or even comparatively measure what "power" is.

I guess it usually means, "is potentially capable of doing more, or with less", so an 8MHz PICAXE is more powerful than a 4MHz, X1's and X2's have more capabilities than non-X1's and non-X2's, a PICAXE with self-contained program may be better than something which requires another chip for memory. It's not so easy to compare two different technologies though or technologies designed for different purposes.

A PC is more powerful than a PICAXE on a number of measurements, but you can't easily use a DS18B20 temperature sensor with one, so is the PICAXE more powerful ?

 

[manie]

I second what Hippy says. Horses for courses ? The Picaxe is certainly easier to connect to the "real world", the PC type chip + ancilliaries again is good in the "virtual world". For controlling stuff like motors and sensing stuff like temperature I think the Picaxe is easier and quicker, it does not require all the support goodies such as Windows etc. So yeah, I'd say the question is what do you want to achieve....