Other parts of Hardware

• Memory
  • We have already discussed registers.
    • This a small amount of memory related to a processor.
    • This memory runs at processor speed.
    • This memory is mostly controlled by the programmer.
    • This memory can not be upgraded or changed.
  • Cache
    • This is memory between two items.
    • Generally a smaller memory item is faster.
    • A bigger memory item is slower
    • Cache helps to "fix" or mitigate this.
    • Hardware wise generally you will have cache between the CPU and memory.
      • Memory is usually slower than the processor.
      • And there is a delay due to the bus.
      • So cache will help to fix this.
    • You also probably have a cache between the disk and other items.
    • Cache can have several layers
      • They get bigger as you go down the layers.
      • They get slower as you go down the layers.
    • Cache usually is part of the CPU "chip" and can not be upgraded.
    • Cache is managed by algorithms in the cache controller.
  • RAM - random access memory
    • This is usually connected to the CPU (cache/registers) via a bus.
    • This is generally slower than the CPU.
    • There are multiple different types of memory that operate at different speeds.
      • Sorry I have not kept up with this.
    • The bus will add some latency.
    • More memory will usually mean better performance.
    • Memory is controlled by the program, and by the OS.
  • All of the above memory is temporary.
    • When the power goes off, memory is cleared.
  • ROM - Read Only Memory
    • This stores the "start up" program for the computer.
    • This is "firmware"
    • There are many versions. EEPROM
    • You really don't need to worry about this.
• Secondary Storage
  • You can think of this as an extension to memory.
  • Related to the previous memory, it is generally:
    • Bigger
    • Slower
    • Cheaper
  • "Disks"
    • Some of them have actual spinning disks.
    • New Solid State Disks are actually memory.
    • SSDs are
      • Faster, MUCH FASTER (10x)
      • More expensive, but less than memory.
      • Very durable wrt dropping.
      • Have a large, but limited number of writes
        • EEPROM "fades" as you perform more writes to the same space.
        • Drives have logic that helps to mitigate this.
  • "Tape"
    • They still exist.
    • Very long term storage.
    • BACKUPS
    • The idea is keep a copy of your data off site.
• Network and the cloud
  • This has become a major part of computing.
  • Essentially on demand computing of all types available over the network
    • Storage
    • Computation resources (cpu cycles)
    • Specialized computing and setups
    • Software.
• Parallel computing
  • Flynn's Taxonomy.