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Components of a computer system - Coggle Diagram
Components of a computer system
Hardware. Physical Components
Input unit
CPU (central processing unit)
Memory unit: principle storage. Stores both data and instructions.
Internal Memory/ Primary Storage/Main Memory. Data and programs are stored temorarily as they are being executed. Limited storage capacity. Functions are; 1) store instructions before processing, 2) hold data being processed and intermediate results of process, 3) store output
RAM (Random Access Memory) The info remains there as long as we are working on application. Temporary storage.
DRAM (Dynamic RAM) needs to be refreshed periodically to retain data
SRAM (Static RAM) faster and expensive than DRAM. Doesn't need to be refreshed. Loses data when power is switched off.
SDRAM (Synchronous Dynamic RAM) uses synchonous interface to transmit large data at high speed increasing efficiency of computer
DDR (Double Data Rate Mmeory) used in Intel Pentium 4 systems. resquires less power. double the speed of SDRAM
ROM (Read Only Mmeory) info can only be read. Stores info permanently (non-volatile) Data can't be modified/removed. primary use is during booting process (INITIAL PROGRAM)
PROM (Programmable ROM) contents stored can be programmed using PROM programmer only once during manufacture. Faster, less expensive approcah for storing
EPROM (Erasable PROM) Erased (by exposing to UV rays) and reprogramed repeatedly
EEPROM (Electronically EPROM) contents cane be erased/reprogrammed in blocks instead of one byte at a time. Also has selective removal
Flash Memory: speacial type of EEPROM. maintains stored info without power source. faster. contents can be erased/reprogrammed in sections. durable. used in memory cards, phones etc.
External Memory/Secondary Storage/ Auxilary Memory. Permanent storage in huge amount. data gets tranferred from secondary to primary for processing. Data can be stored seperately, making it permanent and accessible for long time. speed of retrievel is slower. Eg: Hard disks, CD, DVD etc
ALU: Arithmetic Logic Unit. Performs arithmetic and logical operations on operands.
Control unit: operation of every other component of a computer system. It extracts instructions, decodes them and sends them to ALU. Also called central nervous system of computer. It controls transfer of data and transmits and recieves signals.
Output unit
Software. Collection of programs and procedures that instruct the computer
System Software. Collaction of programs controlling overall working and internal operations.
Operating System. Controlls overall activities. A link b/w user and hardware. first program to get loaded in memory. Eg: Ms DOS (disk operating system),Windows 10, Unix, Linux.
Utility Software. specific tasks related to managing of computer. Eg: Antivirus, backup, disk repair, file management, compression and network programs. Brought from licensed computer stores.
Network Utility: check network conncectivity, speed, configuration of devices etc.
File Manager: viewing, editing, copying, deleting, managing and organizing files
Disk Management: view and manage disk drives, partition drives, format drives, assign drive letters etc.
Scanning: examining computer system, files,drives for possible virus/malware. Done by Antivirus
Backup: storing a copy of data
Compression: shrinking a file so less space is taken. Eg: WinZip, PkZip etc. These files need to be decompressed before reading
Application software. Sets of programs for specific tasks.
General Purpose (Packages): fulfill general needs. Eg: Word processing software (Ms Word, WordPad), Database management (Ms Access, OpenOffice Base, Oracle), Elctronic Spreadsheet (Ms Excel, OpenOffice Clac)
Special Purpose: meet specific needs. also called customised software. Eg: Reservation system, billing system.
Units of Memory
Smallest unit is Bit.
Nibble : 4 bits.
Byte : 8 Bits
Kilo Byte: 1024 Bytes
Mega Byte: 1024 KB
Giga Byte: 1024 MB
Tera Byte: 1024 GB
Peta Byte: 1024 TB
Exa Byte: 1024 PB
Zetta Byte: 1024 EB