Zusammenfassung der Ressource
Unit 1.2 Memory
- ROM
- Non Volatile form of
memory
- Retains its information
through power off
- Contains data that is
pre-written and permanently
written on a ROM chip
- The location of the
POST sequence
- Power On
Self- Test
- BIOS chip
performs
checks
- Makes sure
components
are present
and fuctional
- Once completed successfully,
the OS boots up
- Uses the BIOS
instructions
- Basic Input
Output System
- Considered as
permanent
- Read-Only
Memory
- RAM
- A volatile form
of memory
- Loses its
information at
power off
- Contains the data
and programs
currently in use
- Can be DRAM
or SRAM
- DRAM - Dynamic RAM
- Slower as needs
to be refreshed
thousands of
times per
second
- Cheaper and so
more common
- SRAM - Static RAM
- Faster as doesnt
need to refresh
- Expensive and
Less Common
- Random
Access
Memory
- Flash Memory
- Can be easily
broken
- Relatively
Cheap
- Examples include
USB drives and
Memory Cards
- Can very easily
be broken
and/or stolen
- Can be used to back up
computational data
- Virtual Memory
- A simulated form of
memory found on
the hard drive
- Created by the
Operating System
(OS)
- It is needed to make
more memory than is
actually in the system
- Creates the virtual
memory manager
- Which then creates a
file on the hard drive
- Now the OS can
address the memory
- It's needed when you need to
run things that RAM can't
support.
- Solid State Media
- Contains no
moving parts
- Uses Flash
Memory
- Registers within a computer
- See my Unit 1.1 Revision Map
- There are multiple
forms of register
- Disc Thrashing - The process the
system uses to move data between
Virtual Memory, RAM and Cache.
- Depends on the
frequency of the data,
how often it's used.