Robert J Morton
Robert J Morton |
The personal computer is rapidly evolving from that old familiar user-configurable/upgradeable open system into a short life cycle factory sealed consumer product. In a profit driven global free market this is inevitable. But there is no reason why amateurs should not recreate the flexibility we once enjoyed, and even try to improve on it.
Historical Recap | Design Policy | Physical Structure | False Hope
Option Cards | Internal Devices | External Peripherals | Work Booth
The original PC was built to a sound engineering objective. It was based on a standard steel chassis which housed a standard size motherboard into which standard form option cards were inserted. To add a new function, you just added an option card. To upgrade a function, you simply replaced an option card. The technology of each of the PC's functional areas could thus evolve independently.
This made the original PC not only engineer friendly, but also eco friendly. Theoretically, you could buy an original PC and keep the steel chassis, case and fittings for life. There was no need to dump or recycle the chassis, case and fittings each time there was a leap in technology. You just swapped the naked electronics for a newer, more advanced version. Moreover, you only had to swap the circuit card for the particular function you wanted to upgrade. You did not have to change circuit cards which did not need upgrading. Thus each year, as more and more functionality was crammed into an ever smaller space, the PC could evolve and advance forever within its original chassis.
Since I bought my first IBM PC XT in 1984, I have diligently tried to follow the noble principle of evolutionary upgrade with minimum throw-away. But that's not the way it turned out. Since 1984 I have been forced - by economic expedience and changing standards - to buy 3 completely new PCs, each time relegating my old one to the scrap heap.
I am convinced that this was forced by commercial expedience. A future safe flexible design is not the most profitable. Manufacturers wanted to convert the PC from an engineering innovation into a consumer product. To do this, they had to find a way to either:
PC technology is too near the cutting edge of scientific knowledge and engineering capability for the first option to be practicable. The second option is therefore the one manufacturers seem to have adopted.
The upshot is that manufacturers are building ever more of the PC's functionality into the motherboard. This means that when you want to upgrade a particular function, you must add an option card, yet leave the original functionality in place. This results in unnecessary power consumption and potential operational conflicts. Advances in only a few independent functional areas need take place before your only sensible option is to replace the motherboard. And if you do that, you might just as well replace the whole PC.
Many of the latest PCs and servers have now done away with the standard PC chassis, case and fittings. They are super-thin 1U (1½" high) units with everything on the motherboard. The only way you can add options to these is externally via an appropriate bus. The PC is rapidly metamorphosizing into one of those dreaded black box hermetically sealed consumer products labelled
"Warranty void if seal broken. Contains no user-serviceable components."
For how much longer will the full specification of the commercially available PC be open and published in full and obtainable easily by anybody?
Design Policy
My ideal PC is not a consumer product. It is an open and flexible hardware development environment.
Its physical layout, orientation and placing allow me to install or change an option card, internal peripheral module or the power supply unit; and to connect or disconnect the cables to external peripheral devices:
I must also be able to probe all signal test points on any option card or internal peripheral module with an oscilloscope under the same conditions.
To meet these requirements, my ideal PC is like a conventional horizontal desk top PC which has been:
This does necessitate a slightly different internal arrangement.
My ideal PC is contained in a steel case and chassis whose external width is that of a standard 19 inch rack unit. The case is fixed vertically into a wall recess starting slightly above desk level. It is oriented so that what would be the removable top of a conventional desk top PC system unit becomes the removable front panel.
When this front panel is removed, the PC's internal layout is revealed as shown below at a scale of 2mm per pixel. Click on any component in the following fully mapped diagram for further information about that component.
The internal layout of the chassis is slightly different from that of a conventional system unit. What would be the 'back' of a conventional system unit is at the bottom of my ideal PC's chassis. This so that all connecting cables hang downwards to simplify cable management and to minimise stress on plugs and cables. The power supply is moved across to what would be the 'front' of a conventional desk top system unit. This is so that the removable media devices can be placed on the right hand side of the chassis at a convenient height for the operator.
RF antenna and controller cables attach directly to the tops of their respective modules in the 3½ inch drive bays across the top of the PC chassis.
A False Hope
The predicted and visibly evolving palm top super computer is not for me. Its screen is too small for me to read and cannot fit within its bounds the critical mass of open tasks I need to be able to work efficiently. Its keyboard is too small to be able to type at a sensible speed and with a reasonable degree of ease.
The 'out and about' environment is for me not conducive to creative thought or productive work. The concentration and intensity with which I use a personal computer requires the quiet solitude of my dedicated study booth.
When I am out and about, I want to be free from being hooked into the world of information and communication. I want to experience and enjoy where I am and the people I am with.
This is why my ideal PC is the large static beast I have described.
Sadly, my ideal PC is something I shall never realise. I am a Poor but Right Honourable Fellow of the Ancient and Noble Order of the Long-Term Unemployed. As such I must exist until death upon this miserly pittance called welfare. My ideal PC must forever remain a dream.