Understanding Computer Systems

Computers are what we call computers, which are closely related to our lives. But how much do we know about their composition and development? You need to know that we are professionals and some necessary computer knowledge is essential. Let's take a look at computer systems. Is the main overview of this article:

 

Computer system Classification

Computers are classified into specialized computers and general computers:

Private and general purpose are based on the efficiency, speed, price, and economy and adaptability of computers. General-purpose computers are divided into six categories: supercomputer, mainframe, server, PC, single-chip microcomputer, and multi-core machine. Their structural complexity, performance, and prices are declining in turn. Dedicated computers are our Laptops and Desktops.

 

Five generations of computer changes

 

L first generation: 1946-1957, Electronic Tube COMPUTER: Data Processing

L second generation: 1958-1964, transistor computer: Industrial Control

L The third generation is 1965-1971. Medium and Small integrated circuit computers: small computers

L Generation 4: 1972-1990, large-scale and ultra-large-scale integrated circuit computer: Microcomputer

L The fifth generation started in 1991, with a large scale integrated circuit computer: Single Chip Microcomputer

 

Computer hardware mainly includes the following five categories:

Memory, memory, controller, adapter, and input/output device.

In the early days, the CPU (central processor) was combined with the Controller ). The CPU currently contains memory, so it is called a central processor. The storage program is executed in the order of addresses. This is the operating principle of the Von norm computer and the key to automatic CPU operation. It is the structure of the Von noiman computer and the computer:

 

 

 

Computer software is divided into the following two types:

System programs and applications.

System programs are mainly used to simplify the use of computers, improve the efficiency of computer use, and play and expand the functions and uses of computers, including:

① Various service procedures;

② Language programs;

③ Operating system;

④ Database management system.

An application is a software developed for an application field.

 

Multi-Level Computer System

A computer cannot simply think of it as an electronic device, but a complex combination of hardware and software. It generally consists of more than five different levels, each of which can be programmed ,.

 

Level 5 computer Hierarchy System

L The first level is the microprogram design level. This is a real hardware level, where the hardware directly executes micro commands. If an application is directly written using micro commands, you can run the application at this level.

L Level 2 is generally a machine level, also known as a machine language level. It is interpreted by a microprogram as a machine command system. This level is also a hardware level.

L Level 3 is the operating system level, which is implemented by the operating system program. These operating systems are composed of machine commands and generalized commands, which are software commands defined and interpreted by the operating system. Therefore, this level is also called a hybrid level.

L Level 4 is the assembly language level, which provides programmers with a symbolic language to reduce the complexity of programming. This level is supported and executed by the assembler. If an application is written in assembly language, the machine must have this level of functionality. If the application is not written in assembly language, this level of functionality is optional.

L level 5 is the advanced language level. It is user-oriented and set to facilitate the compilation of applications. This level is supported and executed by compilation programs in various advanced languages.

 

Computer performance indicators are mainly CPU performance indicators. Memory performance indicators and I/O throughput (the amount of information that can be processed within a certain period of time ). So pay special attention to these points when buying computers. You must know that we are learning computers and that these basic knowledge are still required!

 

The following are some other performance descriptions:

ThroughputRepresents the amount of information that a computer can process at a certain interval. The unit is byte/second (B/S ).

Response timeRepresents the time measurement between input validity and system response generation, measured in time units, such as microseconds (10-6S), Nanoseconds (10-9S).

UtilizationRepresents the ratio of the actual time used by the system within a given interval, which is generally expressed as a percentage.

Processor Word LengthThe number of digits that the processor can perform in binary operations. The current processor is 8-bit, 16-bit, 32-bit, and 64-bit.

The longer the word length, the higher the accuracy of the calculation.

Bus widthGenerally, it refers to the binary digits of the internal BUS that are interconnected between the memory and the memory in the CPU.

Storage CapacityThe total number of all storage units in the memory, usually expressed in KB, MB, GB, or TB.

K = 210,M = 220,G = 230,T = 240,B = 8Bit (1Bytes ).

The larger the memory capacity, the more binary memory.

Memory bandwidthMemory speed indicator, the amount of binary data read from the memory per unit of time, which is generally expressed by the number of segments/second.

Clock speed/clock cycleThe CPU cycle is controlled by the master clock. The master clock continuously produces a fixed frequency clock. The frequency of the master clock (f) is calledCPU clock speed. The measurement unit is MHz (Z) and GHz (gihz ). For example, the Pentium series is 60 MHz ~ 266 MHz while pentium4Upgrade3.6 GHz.

The reciprocal of clock speed is calledCPU clock cycle(T), that is, T = 1/f. The measurement unit is microsecond and nanosecond.

CPU execution timeIndicates the CPU time used by the CPU to execute a program. It can be calculated as follows:

CPU execution time = number of CPU clock cycles × CPULong clock cycle

CPIThe number of cycles of each command, that is, the average number of clock cycles required to execute a command. Use the following formula for calculation:

CPI =

Number of CPU clock cycles required to execute a program/number of commands contained in the program

MIPsIt indicates the number of millions of commands per second. It is calculated as follows:

MIPs =

Number of command lines/program execution time × 106

=

Clock frequency/CPI × 106

The execution time te is:

Te =	Number of commands/MIPs × 106

MflopsThe number of millions of floating point operations per second. The following formula is used for calculation:

Mflops =

Number of floating point operations in the Program/program execution time × 106

MIPs is the number of executed commands per unit time, so the higher the MIPs value, the faster the machine.

Mflops is based on operations rather than instructions. It can only be used to measure the performance of a machine's floating point operations, but cannot reflect the overall performance of the machine.

TflopsIt indicates the number of trillion floating point operations per second. This technical indicator is generally used in the supercomputer.

 

Understanding Computer Systems