A computer may be defined as a machine which accepts data from an input device, processes it by performing arithmetical and logic operations in accordance with a program of instructions
Trang 1việc với bất kỳ tập tin flv nào mà bạn tải về từ bất kỳ dịch vụ chia sẻ video nào chứ không chỉ YouTube
Hồng Anh
PC World Mỹ 12/2006
Làm vệ sinh cho các thanh RAM và Card
(Dân trí) - Các thanh RAM và card chức năng (card màn hình, card sound, modem…) lâu ngày sử dụng sẽ bám bụi, nhất là những khe cắm AGP hay PCI trên mainboard Bài viết sẽ hướng dẫn cách làm vệ sinh cho chúng
Có thể dùng cọ quét sơn loại nhỏ hay ống xịt bụi làm sạch bụi bẩn, nhưng riêng đầu cắm (có những chân cắm màu vàng) thì có thể xảy ra hiện tượng hoen ố do bụi bám lâu ngày gây nên
Để làm được việc này thật đơn giản và hiệu quả giúp cho những card của chúng ta luôn mạnh khỏe và bền bạn chỉ cần làm các bước sau:
dùng khăn giấy phủi nhẹ, rồi tiếp tục chà, đến khi nào bạn cảm thấy sáng sủa, hết bụi, vết hoen ố mờ hẳn thì thôi
trên mainboard Xong việc bạn có thể cắm lại vào máy và vận hành tiếp
Hoa Đào
Computer system
Trang 2Computer System
Book I: computer system fundamentals
Chapter 1: INTRODUCTION TO COMPUTER
Question 1 What is a computer?
A computer may be defined as a machine which accepts data from an input device, processes it by performing arithmetical and logic operations in accordance with a program of instructions and returns the results through an output unit
A computer is basically an electronic machine operating on current
Question 2 Components of a Computer system?
A computer system comprises of the following components:
1 Central Processing Unit (CPU)
- CPU is the heart of the whole sys
- CPU consists of the :
Trang 3 program counter (PC)
general purpose register
- The function of each components of CPU:
Control unit:
control and co_ordinate all hardware functions of the CS
examine and decode all program instructions to the computer and initiate their execution by sending the appropriate signals
ALU:
multiplication, division & exponentiation> and logic comparision two values functions required by computer
ACC:
holds the first operand of the temporary result of the ALU
PC:
contains the add of the next instruction to be excuted
IR:
contains the current instruction to be executed
Main memory
MAR:
holds the address location to or from which data is to be transferred
MDR:
contains the data to be written to or read out of the addressed location
SR:
keeps track of the status of the accumalator
General Purpose Register:
for general purpose procedures
Please refer to diagram for an illustratin of the basic components of the CPU
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T
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R
N
A
L
CPU Control unit Arithmetic Logic Unit Accumulator
Program Couter to main Instruction Register memory Memory Address Register
Memory Data Register Status Register
General Purpose Register
Basic components of a CPU
Control Unit
Main Memory
Backing Storage
Control signals Data flow
Components of a CS
2 Input units
- Used to enter data( raw unprocessed facts) and instructions to the computer
3 Output units
- Used for delevering the processed result from the computer in useful form
4 Backing storage units
- Backing storage units need for high capacity data storage devices that can store data in a more permanent form for later retrieral, updating and referencing
- Backing storage is also called secondary storage external storage and auxiliary storage
B
U S
Trang 5Chapter 2: MICOPROCESSOR
Question 1 Cache Memory?
- Cache memory is a small amount of very fast store with faster access time than the main memory
- Cache memory is used to temporaryty store data instructions that are likely
to be retrieved many times, thus speeds up the processing of data
- Sits between main storage and the processor acting as holding area through which all data and instructions pass
- Old data in the cache memory is over written by new then cache is full
Question 2 Virtual Memory?
- Virtual memory makes use of both the main memory and backing store
- In a virtual memory sys, each user has the illusion that his program is in the main memory all the time
- The sys maintains this illusion by keeping some of the “unused” portion of the program’s code and data on a backing store device which is usually magnetic disk
- The movement of the unused portion from the backing store to the mian memory is transparent to the users
- Please refer to diagram for virtual memory
Virtual Memory
Chapter 3: BATCH/ ONLINE AND REAL TIME PROCESSING SYSTEM
Question 1 Batch Processing System?
- Def: Computer processing does not begin until all the input data has been collected and grouped together called Batched Generally data is accumulated for a certain period of time or unitl a certain quantity
- Ads:
Response time is not critical
Need to process large volumn of data
Computer efficiency is more important than response time
- Dis:
Time between recording and processing of source document is long
A3 A1
A2
A2
A3
A1