THE MEMORY ELEMENTS

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THE MEMORY ELEMENTS
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Words in high-speed memory
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Read-write random-access memory
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The Memory Units

• 1 b 1 bit
• 1 Kb 1024 (210) b 1 kilobit
• 1 Mb 1024 (210) Kb 1048576 (220) b 1
  megabit
• 1 Gb 1024 (210) Mb 1073741824 (230) b 1
  gigabit
• 1 Tb 1024 (210) Gb 1099511627776 (240) 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 (210) bytes 1 kilobyte
• 1 MB 1024 (210) KB 1048576 (220) B 1
  megabyte
• 1 GB 1024 (210) MB 1073741824 (230) B 1
  gigabyte
• 1 TB 1024 (210) GB 1099511627776 (240) B 1
  terabyte

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Basic static memory cell
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Linear-select SRAM
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Decoders
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Decoders condt
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Decoders condt
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Two-dimensional static memory cell
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Two-dimensional memory organization
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Two-dimensional memory organization condt
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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
16 64 transistors 16 transistors
4096 49152 transistors 768 transistors
1 megabit (220) ?20 000 000 transistors ?20 000 transistors
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Bus for computer system
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IC package of RAM chip
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Interfacing chips to a bus
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Layout for adding memory to a bus
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Another IC package of RAM chip
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Dynamic random-access memories
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DRAM timing signals in normal and paging mode
operation
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Read-only memories
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Read-only memories condt
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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