Memories - Primary and Secondary
MEMORIES PRIMARY & SECONDARY
Types of Memories
1. ln general. the memory system attached to a computer can be
divided into two major sections referred to as the ‘main’ or ‘primary memory and the ‘backing’ or secondary memory. The main or primary is used hold the program being executed and any data currently in use
The backing memory is used for storing data and program curretly not in use.
The general requirements of the main memory are that it should provide rapid access to data while allowrng a reasonably large storage capacity. Backing storage is requrred to provide enormously large amounts of storage. but speed of data access may be relatively slow.
Primary Memomy
ROMS. The Read Only Memory (ROM) [8 the Simplest kind at memory. It is equivalent to a group of registers. each permanently storing a word. By applying control Signal we can read the word in any memory location. ("read“ means to make the contents of memory location appear at the output terminals of the ROM)
Non-Volatile Memory.
Ms PROMs and EPROMs are nonvolatile memories. ThlS means hat they retain the store data even when the power to the device is shut off.
RAMs.
A Random Access Memory (RAM). also called a w memory/us equrvalent to a group of ddressable re ister After supplying an address. you can either rea e stored contents of the memory location or write new contents into the memory location. ln market mainly two types of RAMs are available and they are SRAM and DRAM.
Volatile Memory
RAMs are volatilememories. This means the stored data in these memories goes off when the power supply is turned off.
MEMORIES PRIMARY & SECONDARY
Types of Memories
1. ln general. the memory system attached to a computer can be
divided into two major sections referred to as the ‘main’ or ‘primary memory and the ‘backing’ or secondary memory. The main or primary is used hold the program being executed and any data currently in use
The backing memory is used for storing data and program curretly not in use.
The general requirements of the main memory are that it should provide rapid access to data while allowrng a reasonably large storage capacity. Backing storage is requrred to provide enormously large amounts of storage. but speed of data access may be relatively slow.
Primary Memomy
ROMS. The Read Only Memory (ROM) [8 the Simplest kind at memory. It is equivalent to a group of registers. each permanently storing a word. By applying control Signal we can read the word in any memory location. ("read“ means to make the contents of memory location appear at the output terminals of the ROM)
Non-Volatile Memory.
Ms PROMs and EPROMs are nonvolatile memories. ThlS means hat they retain the store data even when the power to the device is shut off.
RAMs.
A Random Access Memory (RAM). also called a w memory/us equrvalent to a group of ddressable re ister After supplying an address. you can either rea e stored contents of the memory location or write new contents into the memory location. ln market mainly two types of RAMs are available and they are SRAM and DRAM.
Volatile Memory
RAMs are volatilememories. This means the stored data in these memories goes off when the power supply is turned off.
Secondary Memory
Hard Disk disk pack consists of a number of three, six or more disks mounted about half an inch apart on a central hub, which rotates, spinning the disks at speeds of 50 or more revolutions per second. lnformation is recorded on both sides of each disk as a series of magnetized or non-magnetized spots. information is stored on tracks 'arranged in concentric circles with each character represented by a pattern of bits in sequence on one track. Although varying in length, each track contains same number of characters. Each track is normally sub divided into sectors and information» is accessed track and sector address. .
FIoppyDrives.
Floppy disk drives are the most widely used storage system in PBS. These units store information in the form of tiny, magnetized spots on small flexible diskettes, which can be removed from the drive unit. Once you write any in ormation on the diskette, it wili remain there until the disk is magnetically erased or written over. This information remains on the disk even when it is removed from the disk drive or if power is removed from the system. These diskettes are relatively inexpensive and are easy to transport and store, and can be easily removed and replaced if they become full.
CD-ROM Drives.
All PCs now carry CD-ROM (Compact Disk Read-Only Memory) drives. A CD-ROM can hold up to 700MB of data , approximately the contents of more than 450 floppy isks. it is far easier for a user to install the programme from one CD, instead of swapping multiple floppy disks. CD-ROM drives are available for different speeds, say 24x to 32x speed drives, 50x to 100x etc. it can be attached @ ElDE, USB, PCMCIA and Parallel port in erfaces. They offer a data transfer rates in excess of 1 mbps. Most CD-ROM drives have an analog audio connector a ows musrc CDs to be played via sound card and speakers.
Types of Memories
1. ln general. the memory system attached to a computer can be
divided into two major sections referred to as the ‘main’ or ‘primary memory and the ‘backing’ or secondary memory. The main or primary is used hold the program being executed and any data currently in use
The backing memory is used for storing data and program curretly not in use.
The general requirements of the main memory are that it should provide rapid access to data while allowrng a reasonably large storage capacity. Backing storage is requrred to provide enormously large amounts of storage. but speed of data access may be relatively slow.
Primary Memomy
ROMS. The Read Only Memory (ROM) [8 the Simplest kind at memory. It is equivalent to a group of registers. each permanently storing a word. By applying control Signal we can read the word in any memory location. ("read“ means to make the contents of memory location appear at the output terminals of the ROM)
Non-Volatile Memory.
Ms PROMs and EPROMs are nonvolatile memories. ThlS means hat they retain the store data even when the power to the device is shut off.
RAMs.
A Random Access Memory (RAM). also called a w memory/us equrvalent to a group of ddressable re ister After supplying an address. you can either rea e stored contents of the memory location or write new contents into the memory location. ln market mainly two types of RAMs are available and they are SRAM and DRAM.
Volatile Memory
RAMs are volatilememories. This means the stored data in these memories goes off when the power supply is turned off.
MEMORIES PRIMARY & SECONDARY
Types of Memories
1. ln general. the memory system attached to a computer can be
divided into two major sections referred to as the ‘main’ or ‘primary memory and the ‘backing’ or secondary memory. The main or primary is used hold the program being executed and any data currently in use
The backing memory is used for storing data and program curretly not in use.
The general requirements of the main memory are that it should provide rapid access to data while allowrng a reasonably large storage capacity. Backing storage is requrred to provide enormously large amounts of storage. but speed of data access may be relatively slow.
Primary Memomy
ROMS. The Read Only Memory (ROM) [8 the Simplest kind at memory. It is equivalent to a group of registers. each permanently storing a word. By applying control Signal we can read the word in any memory location. ("read“ means to make the contents of memory location appear at the output terminals of the ROM)
Non-Volatile Memory.
Ms PROMs and EPROMs are nonvolatile memories. ThlS means hat they retain the store data even when the power to the device is shut off.
RAMs.
A Random Access Memory (RAM). also called a w memory/us equrvalent to a group of ddressable re ister After supplying an address. you can either rea e stored contents of the memory location or write new contents into the memory location. ln market mainly two types of RAMs are available and they are SRAM and DRAM.
Volatile Memory
RAMs are volatilememories. This means the stored data in these memories goes off when the power supply is turned off.
Secondary Memory
Hard Disk disk pack consists of a number of three, six or more disks mounted about half an inch apart on a central hub, which rotates, spinning the disks at speeds of 50 or more revolutions per second. lnformation is recorded on both sides of each disk as a series of magnetized or non-magnetized spots. information is stored on tracks 'arranged in concentric circles with each character represented by a pattern of bits in sequence on one track. Although varying in length, each track contains same number of characters. Each track is normally sub divided into sectors and information» is accessed track and sector address. .
FIoppyDrives.
Floppy disk drives are the most widely used storage system in PBS. These units store information in the form of tiny, magnetized spots on small flexible diskettes, which can be removed from the drive unit. Once you write any in ormation on the diskette, it wili remain there until the disk is magnetically erased or written over. This information remains on the disk even when it is removed from the disk drive or if power is removed from the system. These diskettes are relatively inexpensive and are easy to transport and store, and can be easily removed and replaced if they become full.
CD-ROM Drives.
All PCs now carry CD-ROM (Compact Disk Read-Only Memory) drives. A CD-ROM can hold up to 700MB of data , approximately the contents of more than 450 floppy isks. it is far easier for a user to install the programme from one CD, instead of swapping multiple floppy disks. CD-ROM drives are available for different speeds, say 24x to 32x speed drives, 50x to 100x etc. it can be attached @ ElDE, USB, PCMCIA and Parallel port in erfaces. They offer a data transfer rates in excess of 1 mbps. Most CD-ROM drives have an analog audio connector a ows musrc CDs to be played via sound card and speakers.
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dont use unformal language