2844691
Description
Mind Map by lisawinkler10, updated more than 1 year ago
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Created by lisawinkler10
almost 9 years ago
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Computer Hardware
- CPU
- Central Processing Unit carries out all
the processing in a computer by
fetching, decoding and executing data
stored in memory
- Arithmetic and logic unit (ALU) carries
out the arithmetic and logical operations
- The control unit uses
electrical signals to control the
flow of data within the CPU
- All data and instructions are
stored in RAM, as binary numbers
- Arithmetic and logic unit (ALU) carries
out the arithmetic and logical operations
- The boot sequence is a sequence of processes
that contains all the information and
instructions to get the computer up and running
- The boot loader starts this sequence
- After this is completed, control is handed
to the operating system to provide the
programs for the CPU to process
- The boot loader starts this sequence
- CPU clock speed is the speed of the
fetch-execute cycle (determined by a clock chip)
- Clock speed is measured in cycles per second
(hertz, Hz) and processor speeds in gigahertz, GHz
- Clock speed is measured in cycles per second
(hertz, Hz) and processor speeds in gigahertz, GHz
- The CPU cannot access main memory at the same speed as the processor
clock chip; cache memory has access times similar to the CPU speed but is
very expensive (located close to CPU with dedicated connections)
- A typical computer has 8GB of main memory but only 2MB of cache memory
- L1, L2 and L3 cache memory refer
to how close they are to the CPU
- L1 is often located on the
CPU, has a low capacity and
runs at the same speed of
the CPU, L2 is part of the
CPU module, runs close to
speed and is usually larger
and slower than L1 and L3
is on the motherboard and
is larger and slower
- L1 is often located on the
CPU, has a low capacity and
runs at the same speed of
the CPU, L2 is part of the
CPU module, runs close to
speed and is usually larger
and slower than L1 and L3
is on the motherboard and
is larger and slower
- A typical computer has 8GB of main memory but only 2MB of cache memory
- Multi-core processors use multiple CPUs working together so they
can all fetch, decode and execute instructions at the same time
- The advantage is more data is processed simultaneously, the disadvantage
is more complicated operating systems are needed to manage them
- The advantage is more data is processed simultaneously, the disadvantage
is more complicated operating systems are needed to manage them
- Central Processing Unit carries out all
the processing in a computer by
fetching, decoding and executing data
stored in memory
- Memory
- Random access memory
- Volatile (data lost
when turned off)
- Can be accessed and
changed at any time
- Stores programs and data
being used by the computer
- Contains the
operating system
- Large (4GB or more)
- Dynamic RAM needs to be refreshed every few milliseconds and Static hold the
charge meaning the data is faster (but design is more complex so more cost)
- Volatile (data lost
when turned off)
- Read only memory
- Non-volatile
- Programmed during
computer manufacture
- Stores programs and data
being used by the computer
- Contains the
boot program
- Small (1 or 2MB required
for boot program)
- Non-volatile
- Virtual memory is part of the hard drive as an extension
of RAM (used when computer does not have enough
RAM to hold all the data and programs required)
- Data is passed between RAM and virtual memory but access to virtual
memory is slower than RAM so increasing RAM improves performance
- Data is passed between RAM and virtual memory but access to virtual
memory is slower than RAM so increasing RAM improves performance
- Flash memory is a type of ROM that can be rewritten (used
as a portable memory for storing and transferring data)
- Random access memory
- Secondary Storage
- Magnetic hard disks store
the operating system,
installed programs and user
data. They are reliable, have
a high capacity and low cost
- Optical disks transfer files and distribute software. They have
a good capacity and are low cost, lightweight and portable
- CD and DVD-ROMs
are read by lasers
- CD and DVD-ROMs
are read by lasers
- Flash memory consumes little power and has a
good capacity (but less than a hard disk), is used
in hand held devices and is more expensive
- Factors in choosing secondary storage: capacity,
speed, portability, durability, reliability
- Magnetic hard disks store
the operating system,
installed programs and user
data. They are reliable, have
a high capacity and low cost
Media attachments
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