The purpose of the storage unit of the computer is to store the data entered before
processing and also to store the results after processing. The Central Processing Unit [CPU] is
the brain of any computer system. In a computer system all major calculations and comparisons
are made inside the CPU. The CPU is also responsible for activating and controlling the
operations of other units of a computer system.
There are two types of storage devices.
a. Primary storage device
b. Secondary Storage device.
The Random Access Memory requires some times for accessing data and is considered to be the fastest memory. Each bit in a RAM stores information by means of electric charge, where the presence of an electric charge indicates ‘1’ and the absence of an ‘0’. RAM is called Temporary storage, because data persists until the machine is on.
CD-ROM [Compact Read Only Memory] uses a laser beam to record and read data along spiral tracks on a 51/4’’ disk. A disk can store around 650/00MB of information. CD-ROMs are normally used to store data as back up. Using a CD Writer, lot of information can be written on
CD-ROM and stored for future reference.
They are perfect for sharing PowerPoint presentations, digital photos, MPEG video and
MP3s, transporting files between work and home, or sharing files with friends and colleagues.
processing and also to store the results after processing. The Central Processing Unit [CPU] is
the brain of any computer system. In a computer system all major calculations and comparisons
are made inside the CPU. The CPU is also responsible for activating and controlling the
operations of other units of a computer system.
There are two types of storage devices.
a. Primary storage device
b. Secondary Storage device.
a. PRIMARY STORAGE DEVICE OR RANDOM ACCESS MEMORY [RAM]:
Primary storage is usually referred to as Random Access Memory [RAM] because it is possible to randomly select and use any location of this memory to directly store and retrieve data and
instructions. It is also referred to as read/write memory because information can be ‘read’ from a RAM chip also be ‘written’ into it.
instructions. It is also referred to as read/write memory because information can be ‘read’ from a RAM chip also be ‘written’ into it.
The Random Access Memory requires some times for accessing data and is considered to be the fastest memory. Each bit in a RAM stores information by means of electric charge, where the presence of an electric charge indicates ‘1’ and the absence of an ‘0’. RAM is called Temporary storage, because data persists until the machine is on.
ROM
A Read Only Memory [ROM] is one in which information is permanently stored. The
information from the memory can only be read and it is not possible to write fresh information
into it. This is the reason why it is called ROM. When the power supply is switched off, the
information stored inside ROM is not lost as it is in the case of a RAM chip. ROMs are mainly
used by computer manufacturers for storing the micro programs so that they cannot be modified
by the users.
information from the memory can only be read and it is not possible to write fresh information
into it. This is the reason why it is called ROM. When the power supply is switched off, the
information stored inside ROM is not lost as it is in the case of a RAM chip. ROMs are mainly
used by computer manufacturers for storing the micro programs so that they cannot be modified
by the users.
b. SECONDARY STORAGE DEVICES
This section of the memory is also referred to as backup storage because it is used to
store large volume of data on a permanent basis which can be partially transferred to the primary
storage as and when required for processing.
The storage capacity of the primary storage of today’s computers is not sufficient to store
the large volume of time handled by most data processing centres. As a result, additional
memory, called auxiliary memory or secondary storage, is used with most computer systems.
Hard Disk, Floppy Disk, Tape and Compact Disc are the main secondary storage devices.
store large volume of data on a permanent basis which can be partially transferred to the primary
storage as and when required for processing.
The storage capacity of the primary storage of today’s computers is not sufficient to store
the large volume of time handled by most data processing centres. As a result, additional
memory, called auxiliary memory or secondary storage, is used with most computer systems.
Hard Disk, Floppy Disk, Tape and Compact Disc are the main secondary storage devices.
i). Hard Disk:
The hard disk used in the PC is permanently fixed, hard disks with storage capacities of 8 GB, 10GB,
20GB, 40GB, are quite common, the CPU can use the hard disk to load programs and data as well as to store data We should operate the PC within a dust-free and cool room (Preferably air-conditioned) to prevent hard disk crash.
20GB, 40GB, are quite common, the CPU can use the hard disk to load programs and data as well as to store data We should operate the PC within a dust-free and cool room (Preferably air-conditioned) to prevent hard disk crash.
ii). Floppy Disk:
Floppy disk is flexible circular disk of diameter 3.inches made of plastic coated with a magnetic material. This is housed in a square plastic jacket. The floppy disk can store 1.4 Mbytes of data [also called 1.44Mnytes, since it holds 1440Kytes]. Data recorded on a floppy disk is read and stored in a computer’s memory by a device called a floppy disk drive[FDD]. A floppy disk is inserted in a slot of the FDD. Some of the floppies have limited life time. The floppies have to be recycled periodically
to keep them alive. A frequently recycled floppy. [i.e used] will have a life time of 3to 4 years to do recycling take out old floppies occasionally and try to read them once, at least the directory.
to keep them alive. A frequently recycled floppy. [i.e used] will have a life time of 3to 4 years to do recycling take out old floppies occasionally and try to read them once, at least the directory.
iii). Compact Disk:
CD-ROM and stored for future reference.
iv). Tape Drives:
Even though tape drives are one of the oldest of storage technologies, they can still hold
the most data on a single cartridge. A computer tape drive works similar to a tape recorder or a
VCR. A plastic tape ribbon is coated with magnetic particles which are polarized by a magnetic
field generated by the read/write head.
Since tape is a sequential, and not a random- access media, a tape drive has to wind
through a tape to locate a specific bit of data. This makes accessing data slow so tape is mainly
used for system backups and regular archiving of files and records.
Tape dives allow users to backup large amounts of data. Tape drives are capable of
backing up a couple hundred megabytes to several gigabytes of information without having to
spend large sums of money on disks.
the most data on a single cartridge. A computer tape drive works similar to a tape recorder or a
VCR. A plastic tape ribbon is coated with magnetic particles which are polarized by a magnetic
field generated by the read/write head.
Since tape is a sequential, and not a random- access media, a tape drive has to wind
through a tape to locate a specific bit of data. This makes accessing data slow so tape is mainly
used for system backups and regular archiving of files and records.
Tape dives allow users to backup large amounts of data. Tape drives are capable of
backing up a couple hundred megabytes to several gigabytes of information without having to
spend large sums of money on disks.
iv). DLT [Digital Linear Tape]
DLT drives are a robust and durable medium. The DLT segments the tape into parallel
horizontal tracks and records data by streaming the tape across a single stationary head. Released
in 1991 DLT drives are very reliable, high-speed, and high-capacity making the DLT drives an
excellent use for Network backups.
horizontal tracks and records data by streaming the tape across a single stationary head. Released
in 1991 DLT drives are very reliable, high-speed, and high-capacity making the DLT drives an
excellent use for Network backups.
DAT [ Digital Audio Tape ]
The popular choice for tape drives is DAT. This format is best known for digital audio recording
although DAT drives can’t play DAT audio. These drives use a recording technique called helical
scanning which is used in VCRs. The 4mm tape is wrapped round a spinning read/write head that records data in overlapping diagonal tracks. These overlapping tracks allow for high data density and faster data transfer speeds. There are a few DAT standards but the most common is Digital Data Storage [DDS]. DAT tapes can hold 2GB [SSS] to 40GB [DDS-4] of compressed data.
although DAT drives can’t play DAT audio. These drives use a recording technique called helical
scanning which is used in VCRs. The 4mm tape is wrapped round a spinning read/write head that records data in overlapping diagonal tracks. These overlapping tracks allow for high data density and faster data transfer speeds. There are a few DAT standards but the most common is Digital Data Storage [DDS]. DAT tapes can hold 2GB [SSS] to 40GB [DDS-4] of compressed data.
v). Micro Vault USB Storage Media
Micro Vault media plugs directly into the computer’s SB port – and acts just like another drive. It is small, light, Shock-proof and moisture – proof. This nifty flash memory storage device is compact and durable enough to carry in any pocket. The device is recognized automatically when we connect it to the computer. By connecting it via USB, the files can be transferred by dragging and dropping. There are no cables or adaptors needed, no power cord and no driver software to install. It’s compatible with both Macintosh and Windows operating systems, and even comes with software that password protects the contents of the device.They are perfect for sharing PowerPoint presentations, digital photos, MPEG video and
MP3s, transporting files between work and home, or sharing files with friends and colleagues.
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