Week 8 Journal

Guiding questions

• Pick an I/O device (keyboard, scanner, USB thumb drive, etc.). Describe what I/O control method would be best for the device, and whether it should use character or block I/O.

  • USB Thumb Drive - USB drives use the universal serial bus system. It works by dividing the available bandwidth into frames, and the host controls the frames. Frames have 1500 bytes and a new frame is started every millisecond. During a frame, isochronous and interrupt devices get a slot so they're guaranteed the bandwidth they need.

• Based on the "Difference between Serial and Parallel Transmission" table in the web link, give an example of an I/O scenario where serial transmission would be better than parallel transmission. Justify your answer.

  • One I/O device that would benefit from serial transmission is a keyboard. This is because the data from the keyboard goes to the computer with no need for data feedback to the keyboard. It also means you only need a single cable for you keyboard.

Notes

Parallel vs Serial Transmission

Serial Transmission - data-bit flows from one computer to another computer in bi-direction. One bit flows at one clock pulse. Serial transmission uses 8 bits to transfer data with a start and stop bit.

Parallel Transmission - As the name suggests bits are sent at the same time in a parallel manner.

Basic Storage vs Dynamic Storage

Basic storage partitions fixed sizes of the disk when storing data. Dynamic storage allows you create primary partitions, logical drives, and dynamic volumes, on the disk. Dynamic storage only works on dynamic disks typically.

Simple volume vs spanned volume

Simple volume is space allocated on a drive and it does not have to be contiguous. Spanned volume is simply multiple disks for storing. When one is full the next one is used for storage. Striped volume is used for storage in a rotation method.