1.Memory properties
- Storage capacity: it refers to the size of the memory that is the amount of data that can be stored in the memory
- Cost: the cost per bits of storage that is the cost of a storage unit for a given storage capacity
- Access time: the time between when the request is made for read/write operation and the time it take for the request to be completed
Active mode: it refers to the way the data are access from the memory:
- Sequential mode: in this mode, the location in the memory are access in a redefine sequential other
- Random: the location in the memory can be access in any other regardless of the memory location that was access before
- Direct: data are access neither in a random as in the sequential fashion but using a combination of both the modes. In this mode, the access time for all location may be the same or may slidly differ.
Physical characteristics
Physical characteristic, electronic, magnetic, mechanical, and optical volatile.
2.RAM (random access memory)
Coupled or join to the register, a micro computer typically includes a RAM, a memory were individual items can be written and read relatively quickly
A RAM is the computers main memory and holds data and instruction on which the processor is currently working on. The SRAM (static ram) is faster than DRAM (dynamic RAM) but it is also larger. DRRAM holds a data for only a start time, so each memory beat must be periodically re-fresh S-RAM holds data for as long as power is maintained. Both are volatile memory since they loss data when power is off.
3.ROM (read only memory)
The most basic non-volatile today is ROM, the content of which it is freed are the chip factory
- The EE PROM (the electrically erasable programmable ROM) or flash content can be erased by using high voltage electric pulses other types of ROM include
- PROM (programmable read only memory)
- EPROM (erasable programming read only memory)
- Ultra-violet EPROM (UVEPROM).
4.Cash memory
It is commonly used for the memory processor speed mismatch. It is an extremely fast, small memory between CPU and main memory whose access time is closer to the processor speed of the CPU.
5.Memory hierarchy
The CPU is we’re all computing processing take place in the computer but have very limited memory so it relays in other memories to hold data and instruction and to store results. The functionate types of memory in the computer system are:
- Internal processor memory (registers, catches memories)
- Primary memory (RMM) ROM is also classified in this categories because it contains the good from work
- The secondary storage also called auxiliary memory (magnetic disk, optical disk) this is also use as virtual memory when the capacity of the main memory is surpassed.