In reviewing the hardware components of computers from Chapter 1, the CPU coordi

Question

In reviewing the hardware components of computers from Chapter 1, the CPU coordinates the movement of data from one place to another. Thus, each location (word or byte) is given a specific number (called an address or memory address) so the CPU can tell the main memory where to store or retrieve a specific piece of data.

a) Early personal computers use 16-bit addresses, and this limited the size of the main memory to 65,536 bytes (65K). Why would a 16-bit address limit the main memory?

b) How large can the main memory be with 32-bit addresses?

c) How might a machine with 32-bit integers be able to interact with modern storage devices that contain 1 terabyte (240 bytes) of storage?

d) Several new computers utilize 64-bit integers, and 64-bit hardware is becoming more common over time. Could 64-bit architecture easily use storage devices with 1 terabyte (240 bytes) of storage?

e) With advances in technology, future expansions of computer hardware to utilize 128-bit integers certainly will be possible. Do you think 128-bit integers will become common in computers of the future? Why or why not?

Explanation / Answer

(Ans -) (a) " The 8080 was an 8-bit CPU, meaning it processed 8 bits of information at a time. However, it had 16 address lines coming out of it. The ‘‘bitness’’ of a CPU—how many bits wide its general-purpose registers are—is important, but to my view the far more important measure of a CPU’s effectiveness is how many address lines it can muster in one operation. In 1974, 16 address lines was aggressive, because memory was extremely expensive, and most machines had 4K or 8K bytes (remember, that means 4,000 or 8,000) at most—and some had a lot less. Sixteen address lines will address 64K bytes. If you count in binary (which computers always do) and limit yourself to 16 binary columns, you can count from 0 to 65,535. (The colloquial ‘‘64K’’ is shorthand for the number 66,536.) This means that every one of 65,536 separate memory locations can have its own unique address, from 0 up to 65,535."

(b)With 32- bt addresses , the main memory can addresses = 2^32=4 GB of memory.

(c) With the help of paging mechanism , a machine with 32-bit integers be able to interact with modern storage devices that contain 1 terabyte(240 bytes) of storage.

(d)YES, 64-bit architecture easily use storage devices with 1 terabyte (240 bytes) of storage.

(e) Yes, definitely ,128 -bit architecture will be very common in computers in the near future.There are many advantages of using 128-bit architecture:

Advantages :

If you use consider MISD Architecture Diagram , then it will be obvious that large register size will broaden the width of the stream. Think about it in the following way.

You load a large word, 128 bit long in a single register, and then you move on from one single register to another. This is considerably speed up your work. In fact wavefront processors, and other massively parallel architectures may massively benefit form it.

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