Computer Fundamental

note!Answer: A) DMA
Direct Memory Access (DMA) transfers large blocks of data between devices and memory with little CPU involvement.

note!Answer: C) fetch-decode-execute sequence
The CPU repeatedly fetches an instruction from memory, decodes it, and then executes it.

note!Answer: B) bit-byte-field-record-file-database
The data hierarchy goes from bit to byte, then field, record, file, and database.

note!Answer: B) memory unit
A basic microcomputer needs input, output, a processor, and a memory unit to store data and instructions.

note!Answer: A) mathematical intensive scientific applications
Supercomputers are used for heavy numerical computation such as scientific simulations.

note!Answer: A) semiconductor memory
Semiconductor memory such as RAM loses its contents when power is removed, so it is volatile.

note!Answer: A) allow the computer to store data electronically
RAM chips are electronic primary memory that temporarily stores data for the CPU. They are volatile, so they do not store data indefinitely.

note!Answer: D) electrically erasable
EEPROM stands for Electrically Erasable Programmable Read-Only Memory.

note!Answer: C) software available on hardware
Firmware is software permanently stored in a hardware device, such as ROM or flash memory.

note!Answer: B) 1 1/2
Sign 0 is positive. Exponent 101 is 5, minus excess 4 gives 1. Mantissa 1100 is .1100 = 3/4, and 3/4 × 2^1 = 1 1/2.

note!Answer: D) 6 1/4
6 1/4 = 110.01 in binary, which needs 5 mantissa bits after normalizing. The format has only 4 mantissa bits, so it cannot be stored exactly.

note!Answer: C) 00101000
All options are positive, so the smallest has the most negative exponent. 00101000 has exponent 010 = 2, which is -2, giving 0.5 × 2^-2 = 0.125, the smallest of the four.

note!Answer: A) Main memory
Main memory (RAM) gives direct access to any address in nearly the same time. Disks and optical media need mechanical movement to reach data.

note!Answer: D) Flash drives
Flash drives use solid-state memory with no moving parts. Tapes, disks and DVDs all rely on physically moving media or heads.

note!Answer: D) 10001001
Even parity requires an even number of 1s. 10001001 has three 1s, which is odd, so it contains an error.

note!Answer: A) 3
A code with minimum Hamming distance d corrects up to floor((d-1)/2) errors. For d = 8 that is floor(7/2) = 3.

note!Answer: C) ASCII
ASCII stores each digit as a separate character code, so numeric values take more space and are not stored in a compact binary form. The other systems store numbers directly in binary.

note!Answer: B) MIDI
MIDI is a standard for encoding musical notes and instructions. ASCII is for text, while JPEG and GIF are image formats.

note!Answer: A) optical scanner
An optical scanner is an input device, while plotters, speakers and printers are output devices.

note!Answer: D) high-level language
BASIC, COBOL and FORTRAN are human-readable programming languages, which makes them high-level languages.