IT Employment

General discussion


Your computer was designed in 1979!

By GuruOfDos ·
Intel designed the 8086 in 1979. Then came the PC-XT in 1982.

After 286, 386, 486, Pentium, etc. we are 9 steps ahead of when the PC was invented. From the software point of view, the newer CPUs have more opcodes. Code can be tweaked for later CPUs using new instructions to replace chunks of 8086 code. But one problem remains.

Take a brand new Athlon 3GHz. On an old 386 I can create a floppy that will boot DOS 4.01 and run Wordstar. I can boot said Athlon with this disk and it runs Wordstar and allows me to print to my Epson LQ. So my 2003 PC is happy to run 16 year old code.

Each new CPU has to be able to run code written for the last and that means that you can go back several jumps and still have the older code run. Tomb Raider III won't run on an XT, but ALL the new PC CPUs still run the original 8086 opcodes.

The problem with x86 is that it uses the Segmented Memory Model. The max size of a code or data segment is limited to 64kb. No matter how many Mb or Gb a CPU can address it STILL has to do it in 64k chunks and there is still the problem of swapping segments to manipulate memory.

Running an M680xx chip using a Flat Memory Model at the same clock speed as an x86, uses less code (all the seg ops, far calls, etc are not needed) and runs an equivalent program in less time.

Intel should have thought about this years ago. With new technology overcoming the limits of the 8086, drop the original SMM and adopt a flat memory model. Yes, it would mean that upgrading from 8086 to 286 would also mean a new OS and apps but if they had done it early on, then the latest generations of CPUs would have had a better base to build on than the 1979 idea we are stuck with! It is too late now to redesign the 'PC',but if it had been done in the mid 80's then PCs today would be much faster and a 3GHz cpu would REALLY go!

This conversation is currently closed to new comments.

Thread display: Collapse - | Expand +

All Comments

Collapse -

Failed Alternatives

by TheChas In reply to Your computer was designe ...

I think the answer to your question lies in the alternatives that started and then failed.

The biggest among them to date was OS/2!

The general PC market is locked into the Intel / MS model.
We are stuck in a chicken and egg conundrum.
Many people want a new faster OS, but nobody wants to pay for it until there are enough applications.
Of course, the programmers don't want to write code unless there are users who will purchase the end product.

So, until someone is willing to invest the cash required to get a new generation of hardware and software to a level where it can be a contender in the market, we are stuck with this technology.


Collapse -

There is an obvious alternative

by GuruOfDos In reply to Failed Alternatives

The Mac! Since the first days of Apple computers, they have always used the non-Intel FMM. Yes, Macs are different but they still run equivalent apps more efficiently than a PC.

My first forays into simulators in the mid 80's were based on the CBM Amiga A2000, running a 68000 at 7.14 MHz. I also had a 286-12 pc. Both machines had 1Mb of memory and a 40Mb hard disk. The PC ran MS-DOS 4.01 and Win3.0 with Word1.1 and Excel3. The Amiga had AmigaDos and Workbench as the GUI, an equivalent word pro and spreadsheet and both propelled an Oki400 Laser printer. What gave the Amiga the edge was the dedicated GPU, built in stereo audio and the ability to display full colour high res graphics AND output directly to video with no extra hardware. Even though the Amiga clocked at just over half the speed of the 286, it was a much faster machine. The PC had to evolve to a 486 DX2-66 to out-run the Amiga and, without additional hardware for video and audio, it was pretty quiet and not very colourful. If you needed to run PC/DOS apps, or even Windows, you could buy a 'bridge card' with an 80286 cpu and hardware to allow PC software and hardware (the Amiga had 3 ISA slots) to access the a/v capabilities of the Amiga.

I only stopped using the Amiga about 3 years ago. 486/586 users used to laugh at my meagre 40Mb of hdd and 1Mb of Ram compared to their vast hdd's and RAM and as for the 7.14MHz cpu speed...

Of course when I proved that the Amiga only needed that to perform the same tasksthat took all their resources plus a pile of add-on cards,they went away with their tails between their legs.

I only wish that Jack Tramiel hadn't thrown in the towel with the Amiga because I'm willing to bet that if it had evolved for the same time as the PC would outperform it by a factor of 5 for the same clock speed!

Related Discussions

Related Forums