On 2007-03-24, Radium wrote:

I wonder if it is possible to design a PC that does not reqiure any
fans or discs.

Sure, that's easy enough with off the self hardware, with a few
provisos.

This computer uses RAM chips -- instead of magnetic discs -- in to
store information and does not need a CPU because each bit of
information is provided with a processing unit and its own memory.
This would make the PC run much faster and not need any fans or moving
parts. It is entirely chip-based. Since each bit is provided with its
own memory and processing, this would prevent crashes or overheating
from occuring.

Is RAM really appropriate for long term or bulk storage? What
happens when you turn the system off? Even flash isn't really
suited for HDD replacement due to its limited write endurance,
although the situation is improving.

Also, couldn't a PC be built in such a way that it freshly generates
the correct electric signals ["on the fly"] instead of playing them
back from its ROM chips?

Well yes. You indirectly mention microcode later in your post
which is not present on all processors - some instead prefer
so-called 'random logic' (because a schematic appears to have no
discernable pattern or structure). For microcode it's viable
although inflexible - consider the Pentium f00f bug which was
corrected with new microcode. With random logic you'd need a new,
redesigned chip.

For anything other than microcode, it would quickly become impractical.
If you were writing,say, a bottloader, you would have to write your
software and then design a chip from scratch that spat it out.
Such a chip would likely be bigger and slower than a ROM chip.

I am aware that EEPROM is reliable, low power, customizable, reprogram-
able, cheap and proven. But just out of curiosity, my dream PC is hard-
coded [thus not needing any ROM] and also uses RAM chips -- instead of
magnetic discs -- in to store information and does not need a CPU
because each bit of information is provided with a processing unit and
its own memory. This would make the PC run much faster and not need
any fans or moving parts. It is entirely chip-based. Since each bit is
provided with its own memory and processing, this would prevent
crashes or overheating from occurring.

What makes you think a massively parallel system would be more
reliable than a uniprocessor solution? The software is substantially
more difficult to write - the development tools for parallel processing
are fairly crude. Thorough testing is even harder.

You may be interested in looking at the INMOS transputer. That
seems broadly comparable to what you have in mind (apart from this
strange wish for a ROMless computer) and it was designed 20 years
ago.

OS: Windows 98SE
Browser: Mozilla Suite 1.8b

Forget it. Such a fundamentally different architechure would never
run a current version of Windows: too many assumptions about the
underlying architechure are made for that. You'd need custom,
designed from the ground up versions of your software.

The following is a bad analogy but I'll add it anyway.

PC reading info from memory = sample playback synth playing back its
samples of sounds of an FM synth.

PC generating its signals in real-time = an *actual* FM synth freshly-
generating its tones "on the fly".

This appears more confusing than the main thrust of your article
for several reasons, and I suspect you're not altogether clear of
the underlying priciples. But I'm no expert there so I'll leave
that one lie.

--
Andrew Smallshaw