Architect

  • RAM is an acronym for Random Access Memory. Random access means that memory contents can be accessed directly if you know its location.
  • Cache is a type of temporary memory that can be accessed faster than RAM.
  • SATA, hard disk interfaces with other system components.
    • Serial ports send data as a series of pulses along one or two data lines.
    • Parallel ports send data as a single pulse along at least eight data lines.

  • Booth’s algorithm

  • sum-of-products
  • product-of-sums

  • Kmap

  • In little endian machines, the least significant byte is followed by the most significant byte.
  • Big endian machines store the most significant byte first (at the lower address).

  • Stack arithmetic requires that we use postfix notation: Z = XY+.

  • k*2^(m)

  • Temporal locality: Recently-accessed data elements tend to be accessed again.
  • Spatial locality: Accesses tend to cluster.

  • Sequential locality: Instructions tend to be accessed sequentially.

  • In a direct mapped cache consisting of N blocks of cache, block X of main memory maps to cache block Y = X mod N.Thus, if we have 10 blocks of cache, block 7 of cache may hold blocks 7, 17, 27, 37, . . . of main memory.

  • Set associative cache combines the ideas of direct mapped cache and fully associative cache
  • tag, set, and offset
  • the accesses overlap: EAT = H * AccessC + (1 – H) * AccessMM

  • the accesses non-overlap: EAT = H * AccessC + (1 – H) * (AccessMM+AccessC)

  • Write through and Write back

  • S = 1/(1-f)+(f/k)

  • Price/precentage

  • This is a DMA configuration.
  • Notice that the DMA and the CPU share the bus.
  • The DMA runs at a higher priority and steals memory cycles from the CPU.

  • Cycle Stealing is a method of accessing computer memory or bus without interfering with the CPU. It is similar to direct memory access for allowing I/O controllers to read or write RAM without CPU intervention.

  • Hard disk platters are mounted on spindles.
  • Read/write heads are mounted on a comb that swings radially to read the disk.
  • he rotating disk forms a logical cylinder beneath the read/write heads.

  • Data blocks are addressed by their cylinder, surface, and sector.

  • Seek time is the time that it takes for a disk arm to move into position over the desired cylinder.
  • Rotational delay is the time that it takes for the desired sector to move into position beneath the read/write head.
  • Seek time + rotational delay = access time.
    • (60000/rotation speed)/2

  • Mean Time To Failure (MTTF)

  • Redundant Array of Independent Disks
Written on December 16, 2020