memory and storage devices
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- 3. Memory devices: A memory is just like a human brain. It is used to store data and instruction. Computer memory is the storage space in computer where data is to be processed and instructions required for processing are stored The memory is divided into large number of small parts. Each part is called a cell. Each location or cell has a unique address which varies from zero to memory size minus one. 3
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- 5. Static RAM (SRAM) Its is faster and more reliable than DRAM. Its chips utilize less power the SRAM Chips is more expensive then DRAM chips Dynamic RAM (DRAM) DRAM is used for most system memory because it is cheap and small. All DRAMs are made up of memory cells. RAM RAM stands for Random Access Memory . RAM is also called main memory . its consists of memory chips on the mother board. It is read/write memory. Data and instructions are store in it temporarily 5
- 6. PROM (Programmable Read Only Memory). PROM is blank chip which a programmer can write program or data using special device. If any error in data in PROM than we can not erase the data. EPROM (Erasable Programmable Read Only Memory). The data written in EPROM chip can be erased by using special device and ultra –violate rays . EEPROM (Electrically Erasable Programmable Read Only Memory)’ This kind ROM can be written or changed with the help of electrical devices. So data in this type of ROM chip can be easily modified data ROM stands for Read Only Memory. The memory from which we can only read but cannot write on it. This type of memory is non- volatile. The information is stored permanently in such memories during manufacture 6
- 7. A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store or retrieve data. STORAGE DEVICES 7
- 8. STORAGE DEVICES Primary magnetic storage Diskettes Floppy disks Hard disk Magnetic tape Primary optical storage CD,DVD, CD R ,CDRW 8
- 9. FLOPPY DISK: Floppy means soft. Its also called floppies and diskette. Its made by flexible plastic. Its enclosed in cardboard jacket. And now use for transfer small data from one computer to another. 9
- 10. 10 HARD DISK: 1. Hard disks are sealed in a chamber 2. Hard disk consists of a rigid metal platter (usually aluminum) rather than flexible Mylar. 3.Hard disk spin between 3600 rpm and 7200 rpm compared to a diskette 300 rpm.
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- 12. 12 MAGENETIC TAPE: A diskette contains a single flat piece of plastic (the disk) coated with iron Oxide enclosed in vinyl or plastic cover. Its also cheaper. Its used for store files and documents. And also use for transfer information from one computer to another.
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