Lenovo PC 300GL Understanding Your Personal Computer 6267, 6277, 6287 - Page 10

Memory, Microprocessor Cache, Microprocessor Instructions

Get Lenovo PC 300GL PDF manuals and user guides View all Lenovo PC 300GL manuals
Add to My Manuals
Save this manual to your list of manuals

Page 10 highlights

Microprocessors can operate at two clock speeds: an internal speed for operations within the microprocessor and an external speed for transferring data in and out of the microprocessor. Microprocessor Cache Both level-1 (L1) cache and level-2 (L2) cache are integrated with the microprocessor on the system board. Cache is high-speed memory that stores information most often used by the microprocessor. Integrated cache provides a performance increase over the external placement of cache on the system board. Refer to "Cache Memory" on page 4 for more information about cache memory. Microprocessor Bus The microprocessor has an external bus that connects it with main memory and control circuits. This pathway, which is also called the processor bus or local bus, has the same bus width as the microprocessor and operates at the same external speed. Another computer bus, called the I/O bus or expansion bus, carries data and instructions between the microprocessor bus and the computer peripherals. The width of the I/O bus is 32 bits. With advanced bus technologies, the speed of the I/O bus might approach that of the microprocessor bus. With standard bus technology, however, the speed of the I/O bus is much slower than that of the microprocessor bus. Refer to Chapter 2, "Expansion-Bus" on page 8 for additional information. Microprocessor Instructions Data and instructions are necessary for each processing operation that the microprocessor performs. Data and instructions are copied from memory into registers within the microprocessor. Registers are also used to store the data that results from each processing operation until the data is returned to memory. The set of instructions that the microprocessor can perform determines whether the computer can run a particular program. For example, programs written for 32-bit computers require a microprocessor capable of performing 32-bit instructions. Memory Your computer uses several types of memory to store information. This section explains memory concepts, types of memory, and how the types of memory are used. Although a computer is a complex machine, the method it uses to store information is quite simple. All information (data and instructions) is stored in a coded format made up of 0's and 1's. Memory is a series of switches, with an open switch representing a 0 and a closed switch representing a 1. Each switch represents the smallest unit of computer storage, a bit; eight consecutive bits of storage equals a byte. Memory is allocated in kilobytes (KB), megabytes (MB), and gigabytes where 1 KB equals approximately 1 000 bytes, 1 MB equals approximately 1 000 000 bytes, and 1 GB equals approximately 1 000 000 000 bytes. In 1 MB 2 Microprocessors and Memory

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
Microprocessors can operate at two clock speeds:
an
internal speed
for operations within the
microprocessor and an
external speed
for transferring data in and out of the microprocessor.
Microprocessor Cache
Both
level-1 (L1) cache
and
level-2 (L2) cache
are integrated with the microprocessor on the
system board.
Cache is high-speed memory that stores information most often used by the
microprocessor.
Integrated cache provides a performance increase over the external
placement of cache on the system board.
Refer to “Cache Memory” on page
4 for more
information about cache memory.
Microprocessor Bus
The microprocessor has an external bus that connects it with main memory and control
circuits.
This pathway, which is also called the
processor bus
or
local bus
, has the same bus
width as the microprocessor and operates at the same external speed.
Another computer bus, called the
I/O bus
or
expansion bus
, carries data and instructions
between the microprocessor bus and the computer peripherals.
The width of the I/O bus is
32 bits.
With advanced bus technologies, the speed of the I/O bus might approach that of
the microprocessor bus.
With standard bus technology, however, the speed of the I/O bus
is much slower than that of the microprocessor bus.
Refer to Chapter
2, “Expansion-Bus”
on page
8 for additional information.
Microprocessor Instructions
Data and instructions are necessary for each processing operation that the microprocessor
performs.
Data and instructions are copied from memory into
registers
within the
microprocessor.
Registers are also used to store the data that results from each processing
operation until the data is returned to memory.
The set of instructions that the microprocessor can perform determines whether the
computer can run a particular program.
For example, programs written for 32-bit
computers require a microprocessor capable of performing 32-bit instructions.
Memory
Your computer uses several types of memory to store information.
This section explains
memory concepts, types of memory, and how the types of memory are used.
Although a computer is a complex machine, the method it uses to store information is quite
simple.
All information (data and instructions) is stored in a coded format made up of 0’s
and 1’s.
Memory is a series of switches, with an open switch representing a 0 and a closed
switch representing a 1.
Each switch represents the smallest unit of computer storage, a
bit
;
eight consecutive bits of storage equals a
byte
.
Memory is allocated in
kilobytes (KB)
,
megabytes (MB)
, and
gigabytes
where 1 KB equals approximately 1 000 bytes, 1 MB equals
approximately
1 000 000
bytes,
and
1
GB
equals
approximately
1 000 000 000
bytes.
In 1 MB
2
Microprocessors and Memory