THE MEMORY ELEMENTS
Words in high-speed memory
Read-write random-access memory
The Memory Units 1 b – 1 bit 1 Kb = 1024 (2 10 ) b – 1 kilobit 1 Mb = 1024 (2 10 ) Kb = (2 20 ) b – 1 megabit 1 Gb = 1024 (2 10 ) Mb = (2 30 ) b – 1 gigabit 1 Tb = 1024 (2 10 ) Gb = (2 40 ) b – 1 terabit 1 byte = one 8 bit word (a sequence of 8 bits at the same address) 1 B – 1 byte 1 KB = 1024 (2 10 ) bytes – 1 kilobyte 1 MB = 1024 (2 10 ) KB = (2 20 ) B – 1 megabyte 1 GB = 1024 (2 10 ) MB = (2 30 ) B – 1 gigabyte 1 TB = 1024 (2 10 ) GB = (2 40 ) B – 1 terabyte
Basic static memory cell
Linear- select SRAM
Decoders
Decoders condt
Two-dimensional static memory cell
Two-dimensional memory organization
Two-dimensional memory organization condt
Comparison of numbers of electronic elements used in one-dimensional and two-dimensional systems of memory Number of memory cells Linear selection Two- dimensional selection 1664 transistors16 transistors transistors768 transistors 1 megabit (2 20 ) transistors transistors
Bus for computer system
IC package of RAM chip
Interfacing chips to a bus
Layout for adding memory to a bus
Another IC package of RAM chip
Dynamic random-access memories
DRAM timing signals in normal and paging mode operation
Read-only memories
Read-only memories condt
Types of read-only memories MROM (Eng. Mascable ROM) PROM (Eng. Programmable ROM) EPROM (Eng. Erasable and programmable ROM) EEPROM (Eng. Electrically erasable and programmable ROM) An important application of EEPROM: Flash-BIOS