3670648
Description
Mind Map by Rose Cozens Unkn, updated more than 1 year ago
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Created by Rose Cozens Unkn
over 8 years ago
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RAM & ROM
- ROM
- ROM is memory that cannot be
changed by a program or user. ROM
retains its memory even after the
computer is turned off. For example,
ROM stores the instructions for the
computer to start up when it is
turned on again.
- ROM: READ ONLY MEMORY
- ROM is memory that cannot be
changed by a program or user. ROM
retains its memory even after the
computer is turned off. For example,
ROM stores the instructions for the
computer to start up when it is
turned on again.
- A computer uses two types of storage. A main store
consisting of ROM and RAM, and backing stores
which can be internal, eg hard disk, or external, eg a
CD or USB flash drive.
- RAM
- RAM is a fast temporary type of memory
in which programs, applications and data
are stored.
- EXAMPLES OF WHAT'S STORED IN RAM:
- The operating system
- Applications
- The graphical user interface
- The operating system
- EXAMPLES OF WHAT'S STORED IN RAM:
- RAM: RANDOM ACCESS MEMORY
- RAM (Random Access Memory) is the primary memory
used in a computer. Its individual memory cells can be
accessed in any sequence, and therefore it is called the
random access memory. RAMs are divided in to two
categories as Static RAM (SRAM) and Dynamic RAM
(DRAM).
- SRAM uses transistors to store a single bit of
data and it does not need to be periodically
refreshed. DRAM uses a separate capacitor to
store each bit of data and it needs to be
periodically refreshed to maintain the charge in
the capacitors
- SRAM uses transistors to store a single bit of
data and it does not need to be periodically
refreshed. DRAM uses a separate capacitor to
store each bit of data and it needs to be
periodically refreshed to maintain the charge in
the capacitors
- Static RAM
- SRAM is a type of RAM and it is a volatile memory,
which looses its data when the power is turned
off. In a SRAM, each bit that stores data is made
up of four or six transistors that make up a
flip-flop. There are additional transistors that are
used to control read and write accesses of storage
cells. Even though typical SRAMs use six
transistors to store each bit, there are SRAMs that
use eight, ten or more transistors to store a single
bit. When the number of transistors is reduced,
the size of the memory cell decreases. Each SRAM
cell can be in three different states called read,
write and standby. A cell is in the reading state
when data has been requested and it is in writing
state when the data in the cell is modified. The
cell is in the standby state when it is idling.
- SRAM is a type of RAM and it is a volatile memory,
which looses its data when the power is turned
off. In a SRAM, each bit that stores data is made
up of four or six transistors that make up a
flip-flop. There are additional transistors that are
used to control read and write accesses of storage
cells. Even though typical SRAMs use six
transistors to store each bit, there are SRAMs that
use eight, ten or more transistors to store a single
bit. When the number of transistors is reduced,
the size of the memory cell decreases. Each SRAM
cell can be in three different states called read,
write and standby. A cell is in the reading state
when data has been requested and it is in writing
state when the data in the cell is modified. The
cell is in the standby state when it is idling.
- Dynamic RAM
- DRAM is also a volatile memory that uses separate
capacitors to store each bit. Capacitors when not
charged represent the value 0 of a bit and when charged
represent the value 1. Since the capacitors discharge
with time, they need to be refreshed periodically to
maintain the values stored in them. Each memory cell in
a DRAM consists of a capacitor and a transistor and
these cells are arranged in a square array. DRAMS are
widely used for main memories in personal computers
and game stations since they are cheaper. DRAMs are
manufactured as integrated circuits (ICs) that come in
plastic packages with metal pins that could be connected
in to busses. Currently there are DRAMs in the market
that are manufactured as plug-in modules, which are
easier to handle. Single In-line Pin Package (SIPP), Single
In-line Memory Module (SIMM) and Dual In-line Memory
Module (DIMM) are some examples of such modules.
- DRAM is also a volatile memory that uses separate
capacitors to store each bit. Capacitors when not
charged represent the value 0 of a bit and when charged
represent the value 1. Since the capacitors discharge
with time, they need to be refreshed periodically to
maintain the values stored in them. Each memory cell in
a DRAM consists of a capacitor and a transistor and
these cells are arranged in a square array. DRAMS are
widely used for main memories in personal computers
and game stations since they are cheaper. DRAMs are
manufactured as integrated circuits (ICs) that come in
plastic packages with metal pins that could be connected
in to busses. Currently there are DRAMs in the market
that are manufactured as plug-in modules, which are
easier to handle. Single In-line Pin Package (SIPP), Single
In-line Memory Module (SIMM) and Dual In-line Memory
Module (DIMM) are some examples of such modules.
- RAM is a fast temporary type of memory
in which programs, applications and data
are stored.
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