1.1 Flashcards
1.1.3
1. What is primary storage?
2. What is secondary storage?
3. What is virtual storage?
- Primary storage: memory, which is made up of RAM (volatile) and ROM. It is directly accessible by the CPU.
- Secondary storage: storage that is non-volatile. It is not directly accessible by the CPU.
- Virtual storage: storage that appears to be local but is physically located elsewhere.
1.1.3
1. What is optical media?
2. What are the advantages and disadvantages?
- Optical media: can be used to store songs, videos and multimedia files. Data is stored on pits and lands, generally circulating outwards from the centre. 2. Disadvantage: less storage capacity compared to other types. Must have an appropriate reader.
1.1.3
1. What is magnetic media?
2. What are the advantages and disadvantages?
- Magnetic: multiple disk platters with a read/ write head.
- Advantage: is cheap and has a vast storage capacity. Disadvantage: has lots of mechanical moving parts, durability is an issue. Consists of two surfaces, each of which contains concentric circles (tracks) with each track divided into sectors.
1.1.3
1. What is solid state media?
2. What are the advantages and disadvantages?
- Solid state: Uses non volatile flash memory to store information. Uses: personal handheld devices, tables, smartphones, military all terrain laptops.
- Advantages: highly durable, very fast read/ write speeds, no noise, no mechanical moving parts.
What are the common features that both RAM and ROM contain?
- Both primary storage/main memory
- Both allow random access
- Both can store programs
- Connected to CPU via buses
What are the features that RAM contain?
Properties of RAM
access memory
Used to store programs and data currently in use
Write speed considerably faster than ROM write speed (large number of write cycles)
Faster to access than secondary storage
Nowadays, faster to read than ROM
Volatile
2 types – DRAM (dynamic RAM – used for main memory), SRAM (static RAM – provides shorter access time than DRAM, used for cache memory)
Used for buffers, eg. print buffer. Many printers will have their own RAM
What are the features that ROM contain?
Properties of ROM
Read Only Memory
Small Capacity
Data stored in ROM can only be modified slowly, with difficulty, or not at all
Non volatile (persistent)
Used to store BIOS (firmware)
EEPROM – Electrically Erasable Programmable Read Only Memory is the type of ROM that stores BIOS and UEFI
Embedded OS likely to be stored in ROM
- Why is RAM called random access?
- Describe the process that occurs when RAM is running low
- RAM is called “random access” because any storage location can be accessed directly.
- An area of secondary storage used by the OS as RAM. The operating system’s memory manager uses secondary storage such as the hard disk or flash drives as RAM. Pages/segments that have not been used recently are moved out of RAM to virtual memory. In the example above, if the user wanted to use program F (currently not in RAM), existing page(s) which are not being used are moved from physical RAM to virtual memory to make space.
- What software items are stored in ROM and why is ROM necessary?
- State one item that needs to be stored in RAM and give a reason why RAM is used
- Explain how paging and segmentation make more efficient use of memory.
- -User files/software/OS currently in use
-User must be able to alter contents of file/computer needs access to
software but needs to be able to replace it
- RAM offers direct access.
- RAM operates at a much faster speed than most secondary storage devices - -Boot file/program/BIOS
-Must be available when computer switched on ( therefore must be
stored on medium which is non-volatile)
- The boot program/BIOS must not be deleted/unintentionally
amended (and therefore is best stored on a read-only medium.) - Allow programs to be stored in non contiguous memory locations - new programs can fit around existing programs in RAM. Allows pages to be transferred to and from secondary storage (i.e. virtual memory).
