What is the storage capacity of a standard single-sided, single-layer DVD?
- A.700 MB
- B.1.44 MB
- C.4.7 GB
- D.25 GB
Correct answer
Explanation
The correct answer is C, 4.7 GB. A Digital Versatile Disc uses a shorter wavelength laser and finer pits than a compact disc, so one side with one recording layer holds about 4.7 GB; a double-layer disc of the same size holds roughly 8.5 GB.
Option A, 700 MB, is the capacity of an ordinary compact disc, the figure most often mixed up with the DVD in the examination hall. Option B, 1.44 MB, is the capacity of the 3.5-inch floppy disk, a number still asked because it appears in old syllabuses. Option D, 25 GB, is one layer of a Blu-ray disc, which reads with a blue-violet laser of even shorter wavelength. Learn these four capacities together as a set, because a question often lists all of them and asks for one: 1.44 MB, 700 MB, 4.7 GB and 25 GB.
Read the full article: Memory and Storage: RAM, ROM, Cache and Units
Practice Questions
View allWhich of the following is the fastest memory in a computer system?
- A.Cache memory
- B.Register
- C.Main memory
- D.Hard disk
Show answer
A register is built into the CPU itself and holds the word the arithmetic and logic unit is operating on at that instant, so it is read and written in a single clock cycle.
Read the full explanation →How many bits make one nibble?
- A.2 bits
- B.4 bits
- C.8 bits
- D.16 bits
Show answer
A nibble is half a byte, that is four binary digits, and it matters because one nibble is written as exactly one hexadecimal digit, from 0 to F. That is why memory addresses in hexadecimal are read four bits at a time.
Read the full explanation →Which type of memory has to be refreshed thousands of times per second to retain its contents?
- A.SRAM
- B.DRAM
- C.ROM
- D.Flash memory
Show answer
Dynamic RAM stores each bit as a charge on a very small capacitor, and that charge leaks away in a few milliseconds, so the memory controller has to read and rewrite every cell continuously.
Read the full explanation →The contents of an EPROM chip are erased by exposing it to
- A.An electrical signal
- B.Ultraviolet light
- C.A magnetic field
- D.Infrared radiation
Show answer
An Erasable Programmable Read Only Memory chip carries a small quartz window over the silicon; ultraviolet light shone through that window releases the trapped charge from every cell at once and returns the chip to its blank state, after which it can be programmed again.
Read the full explanation →One terabyte is equal to how many gigabytes?
- A.100 GB
- B.512 GB
- C.1,024 GB
- D.2,048 GB
Show answer
Every step in the ladder of storage units multiplies by 1,024, because 1,024 is 2 raised to the power 10 and memory is addressed in binary.
Read the full explanation →