{ "q01": { "type": "blank", "question": "\n\nIn a typical computer, the CPU is connected to I/O devices via a hierarchy of\ncommunication busses or interconnects:\n\n
    \n\n
  1. ____ bus: This is the interconnect between the CPU and main memory.
  2. \n\n
  3. ____ bus: This is the interconnect between the CPU and\nhigher-performance devices such as GPUs.
  4. \n\n
  5. ____ bus: This is the interconnect between the CPU and slower devices\nsuch as disks and mice.
  6. \n\n
\n\nWhile some I/O devices are simple, more complex I/O devices may include a\nsimple ____ and some general purpose ____. They may even require ____ or\nsoftware embedded in the device to implement certain aspects of its\nfunctionality.\n\n
\n" }, "q02": { "type": "multiple", "question": "\n\nRegarding interacting with I/O devices, which of the following statements\nare true (choose all that apply)?\n\n\n", "responses": { "pio_poll": "Programmed I/O (PIO) involves the OS polling the I/O device.", "interrupts": "Interrupts allow the OS to overlap computation and I/O.", "efficiency": "Using interrupts are always more efficient than PIO.", "dma": "The direct memory access (DMA) orchestrates transfers between devices and main memory so the CPU doesn't need to.", "drivers": "The OS abstracts the interaction with I/O devices via device drivers." } }, "q03": { "type": "blank", "question": "\n\n

\nLike main memory, modern disk drives can be viewed as an array of ____.\nAlthough multi-sector operations are possible, manufacturers only\nguarantee that a single ____ byte write is atomic. \n

\n\n

\nIn terms of geometry, a modern disk consists of one or more circular hard\nsurfaces called a ____ on which data is stored persistently by inducing\nmagnetic changes to it. These disks are bundled together around the\n____, which is connected to a motor that surfaces around at a constant\nrate measured in ____. The data on these surfaces are encoded in\nconcentric ____, which are tightly packed together on the surface.\n

\n\n

\nTo read and write from the surface, a ____ is moved to position the ____\nover the desired portion of the disk.\n

\n\n
\n" }, "q04": { "type": "multiple", "question": "\n\nRegarding disk drives, which of the following statements are true (choose\nall that apply)?\n\n\n", "responses": { "delay": "The rotational delay is the time it takes for the a desired sector to rotate to the disk head.", "seek": "A seek involves moving the disk arm to the appropriate track and is costly.", "coasting": "When a disk arm is coasting, it is stationary and waiting for the appropriate track.", "settling": "After as seek, there is a settling time to ensure the disk head is over the appropriae track.", "back": "Write-back caching appears faster but can be dangerous." } }, "q05": { "type": "order", "question": "\n\nAs with processes, the OS can schedule the order of I/O requests using a\nvariety of disk scheduling algorithms. Match the following definitions\nwith their labels.\n\n
    \n \n
  1. This strategy involves sweeping across the disk and servicing\n requests as it moves across the tracks.
  2. \n\n
  3. This strategy orders the queue of I/O requests by track and picks\n the nearest tracks to complete first.
  4. \n\n
  5. This strategy selects the track with the shortest access time,\n factoring in seek and rotational time.
  6. \n\n
\n\n
\n", "responses": { "ssft": "Shortest Seek Time First", "elevator": "Elevator", "sptf": "Shortest Positioning Time First" } }, "q06": { "type": "blank", "question": "\n\n____ is a technique for using multiple disks to build faster, bigger, and\nmore reliable storage system. Although these systems consist of multiple\ndisks, the aggregation itself appears a single disk device with improved:\n\n
    \n
  1. ____: due to parallel I/O operations.
  2. \n
  3. ____: due to the use of multiple large disks.
  4. \n
  5. ____: due to spreading data across multiple disks.
  6. \n
\n\nTo do this, these multi-disk configurations can use ____ where two copies\nof data is stored, or ____ where blocks are stored across multiple disks.\n\n
\n" }, "q07": { "type": "order", "question": "\n\nMatch the following descriptions with the correct RAID strategy.\n\n
    \n \n
  1. In this strategy, we have only perform mirroring.
  2. \n
  3. In this strategy, we have striping but no redundancy.
  4. \n
  5. In this strategy, we rotate the parity block across multiple disks.
  6. \n\n
\n\n
\n", "responses": { "raid0": "RAID 0", "raid1": "RAID 1", "raid5": "RAID 5" } } }