1) Location
- CPU registers
- Cache
- Internal Memory(main)
- External (secondary)
- Word size : Typically equal to the number of bits used to represent a number and to the instruction length.
- For addresses of length A (in bits), the number of addressable units is 2^A.
3) Unit of Transfer
- Word
- Block
4) Access Method
* Sequential Access
- Access must be made in a specific linear sequence.
- Time to access an arbitrary record is highly variable.
- Individual blocks or record have an address based on physical location.
- Access is by direct access to general vicinity of desired information, then some search.
- Access time is still variable, but not as much as sequential access.
- Each addressable location has a unique, physical location.
- Access is by direct access to desired location,
- Access time is constant and independent of prior accesses.
- Desired units of information are retrieved by comparing a sub-part of unit.
- Location is needed.
- Most useful for searching.
* Access Time (Latency)
- For random access memory, latency is the time it takes to perform. A read or write operation that is the time from the instant that the address is presented to the memory to the instant that the data have been stored available for use.
- Access time + additional time required before a second access can begin(refresh time, for example).
- Generally measured in bit/second.
HI FRIENDS I AM DHANESH. I ADD THIS BLOG FOR AN EDUCATION PURPOSE