Computers
Contents
History
The first computer was invented in the 40's and was called ENIAC. It's enough to say it was very expensive, very hard to use, and it couldn't do much. But it was a huge step for mankind. In the 60's the TTL was invented. The TTL was the beginning of the microprocessors. It took a few years before we could build computers for the ordinary people. The nerds had to wait until the late 70's before they could buy a computer. In the early 80's IBM decided to make a computer. They made the first PC, and the rest is barely history. One thing I find interesting is the development of the TTL. It took about 10 ns to calculate something for the first TTL-family. Nowadays, it takes about 2-3 ns to calculate the same thing. With that in mind, it's amazing the speed of the computers have increased so much. That is accomplished by using more transistors in the processor. One early processor had 2300 transistors. Nowadays they have millions!
Why memory?
A P200 with 4 Mb RAM can be slower than a 486 with 32 MB RAM! When the processor is about to calculate something it must have an instruction first. That's why we have memory in our computers. The instructions are hopefully stored in the RAM memory, because the processor will only have to wait for about 70 ns then. If it had to wait for 70 ns for each instruction, it could calculate about 10 000 000 instructions per second (some delay for the calculations are included). Sometimes the RAM can't store all instructions, then the computer can put them on the harddrive instead. The processor have to wait for about 10 ms when the instructions are stored there. That would meen 100 instructions per second. That's a big difference : 10 000 000 and 100. We have the same difference between cache and RAM. There's no need to get uppset if you don't have cache memory, 70 ns is quite fast.
Is something false?
This document was created 96-12-13 (Friday 13:th!)