Test 1 RAM ROM Cache, Secondary memory Flashcards
Explain primary memory (3)
the only storage that is directly accessible by the CPU
The primary memory holds both data and instructions that are currently running on the computer system
These data and instructions are stored in the primary memory as binary machine code
What does the primary memory contain (2)
Random Access Memory (RAM)
Read Only Memory (ROM)
Explain RAM (4)
type of primary memory that temporarily stores data that the CPU is actively using
Volatile, data is lost once computer is turned off
Instructions and data in the RAM are stored in unique memory locations and every such location has an address
RAM affects computer performance, More RAM —-> Better performance
Explain ROM (3)
Type of primary memory that stores data that cannot be changed or overwritten, meaning it stores permanent data
Non-volatile, ROM retains contents even when computer is turned off. Stores important data (firmware, BIOS)
Holds data and instructions in unique memory locations
Define BIOS
A small program inside ROM that allows the computer to know what to do to find the operating system to ‘boot’
Define Cache
small, high speed memory used to hold frequently used data, so that the CPU doesn’t need to access the much slower DRAM as frequently. It contains SRAM technology
Compare DRAM with SRAM
SRAM is more expensive than DRAM and so DRAM is more preferred for the main RAM of the system
Why does cache speed up processing (3)
Cache can be accessed faster than RAM from the CPU
It holds frequently used instructions and data
Uses SRAM technology and this memory doesn’t need to be refreshed constantly.
How many levels of cache are there?
2 levels
Where does level 1 of cache reside
L1 cache is placed on the microprocessor itself
Where does level 2 cache reside
L2 cache is placed between the primary memory and microprocessor
Explain secondary storage (3)
type of computer storage that is used for long-term data storage
Stores data and programs that are not currently being used or accessed by the computer’s CPU
Has slower access speed but much larger storage capacity than primary memory
List the types of secondary storage (5)
Hard disk drives (HDD)
Solid State Drives (SSD)
Optical discs (CD, DVD)
Cloud storage
Magnetic tapes
How does HDD work (6)
Uses platters
Platters divide into tracks
Platter is spun
Read Write arm moves over platter
Magnetic field control magnetic dots of data
magnetic field determine binary value
Features of SSD (2)
Non-volatile memory
Uses NAND flash memory
Advantages of SSD over HDD
No moving parts (more reliable in portable devices, EG: laptop)
uses less power
Smaller (good for portable devices)
Faster data access
Advantages of HDD over SSD (3)
Cheaper for large amounts of data
Greater longevity for read and write functions
Expensive to change technology to SSD
Define virtual memory
memory management capability of an OS that uses hardware and software to allow a computer to compensate for physical memory shortages by temporarily transferring data from RAM to secondary storage.
Key feature of virtual memory
paging
Explain paging
Allows similar sized sections of data; identified by specific addresses to be swapped between RAM and secondary storage
Primary memory is divided into page files, swap files, and sections so that data can be transferred
The address of these sections in primary memory is linked to a virtual address in secondary storage and the links stored in a table
When a page is needed, the table is accessed to recall the page into the correct location in the RAM
