preface
The Road to Linux series is the book of “Bird brother Linux private house dishes” reading notes, roughly according to the book to make a summary.
Computer Fundamentals
The CPU architecture
- Reduced Instruction Set Computer (RISC)
As the name implies, a simplified instruction set with short execution time, simple behavior, and complex actions performed by multiple instructions. 2. Complex Instru Set Computer (CISC)
It is characterized by a large number of instructions and complexity, but rich behavior. Intel VIA AMD is in use
Origin of X86: Intel’s earliest production of CPU code 8086, and later produced 80286, 80386… Hence the name X86 for the CPU of this architecture. 64-BIT cpus are called X86_64
CPU external frequency and frequency doubling
External frequency refers to the SPEED of data transmission between THE CPU and external components, and frequency doubling is a multiple of CPU internal used to speed up the performance of the work. The multiplication of the two is the CPU frequency speed. Internal frequency = external frequency * multiple frequency
A unit of capacity and speed
General capacity is calculated in binary and speed in decimal. To simplify the calculation, set 1Byte to 8 bits (the Byte is uppercase and the bit is lowercase). For example, the actual size of a 1 gb file is 1024 x 1024 x 1024 Bytes, and the CPU speed is 1GHz =1000 x 1000 x 1000 Hz.
| Carry system | Kilo | Mega | Giga | Tera | Peta | Exa | Zetta |
|---|---|---|---|---|---|---|---|
| binary | 1024 | 1024K | 1024M | 1024G | 1024T | 1024P | 1024E |
| The decimal system | 1000 | 1000K | 1000M | 1000G | 1000T | 1000P | 1000E |
Network speed
The unit of Mbits/second is divided by 8 (1Byte=8 binary digit), which means that 100/50 mbit /s transfer speed is 12.5/6.25 mbit /s download speed.
Hard disk profiteers?
Friends who just bought a computer may be very confused, why the actual capacity of the marked 1TB hard disk is only about 930GB, after checking online, I learned that the hard disk manufacturer is calculated in decimal units, so 1T=1000GB=1000*1000*1000*1000 Byte. This translates to about 931GB in binary. In the heart can not help but curse profiteer, in fact, the hard disk manufacturer of this pot back of a little injustice. The minimum physical quantity of a hard disk is 512Bytes(currently 4 kbytes). The minimum unit is sector. The capacity of a hard disk is determined by the number of sectors n, which can only be expressed in decimal notation to avoid unnecessary trouble.
The main board
The motherboard is used to connect the various components of the computer so that they work together. Upgrade hardware should be careful to match the motherboard.
The bus
The bus completes the connection composition function. Three bus structure was used earlier: data bus, address bus and control bus.
bandwidth
Currently, the memory control chip in the CPU works on the memory at a maximum of 3200MHz, that is, the number of data transfers per second. Most data transfers are 64 bits per second. Therefore, the CPU can obtain the highest memory bandwidth of 3200MHz x 8 Bytes=25.2 GBytes.
A wide
32-bit CPU and 64-bit CPU refer to the data width that the CPU can process at a time, namely the bit width.
32-bit CPU supports up to 4GB of memory?
This is a combination of hardware and software.
Hardware: the address bus of a 32-bit CPU is 32 bits (on some servers it is 36 bits), so the addressable physical address range provided is 2^32=4GB. 64-bit cpus typically have 36 bits of address bus (40 bits for some servers), which is 2^36=64GB.
Software: The 32-bit Windows logical address code uses 32 bits of address, so the logical address range provided by the operating system is 4GB, and some logical addresses are mapped to physical addresses such as BIOS, CPU registers, etc. (see MMIO). The available memory is less than 4GB.
memory
DDR3 and DDR3L differences
DDR3 operating voltage is 1.5V,DDR3L operating voltage is 1.35V. It is usually used in laptops that require high power consumption. If the DDR3L is inserted into an unsupported mainboard, it will burn up.
Dual channel
The maximum bus width of single memory is only 64 bits, and the dual channel can be up to 128 bits. This is the design concept of dual channel.
The hard disk
Default read/write location
Because the outer track area of a disk disk is larger and can accommodate more sectors, data is written from the outer track by default.
SATA interface
SATA transmission interface transmission, when the transmission of 10 bits of code, only 8 bits of data, the other two bits for the check bit. For bandwidth calculations, use a conversion of 1:10 instead of 1:8
Why does an abnormal shutdown damage a mechanical hard disk?
During a normal shutdown, the operating system will return the robot arm to its original position without damaging the hard disk or the robot arm.
Proper nouns
DRAM: Dynamic Random Access Memory
SRAM: Static Random Access Memory Static Random Access Memory
DDR: Double Data Rate
HT: Hyper-threading.
FSB: Front Side Bus speed. ROM : Read Only Memory. VGA : Video Graphics Array. SSD : Solid State Disk. HDD : Hard Disk Drive.