Memory Units — Set 5

Correct Answer: B. Bit

• **Bit** = A bit is the smallest unit of digital information, capable of holding exactly one binary value — 0 or 1; every larger memory unit (nibble, byte, kilobyte, and beyond) is constructed by grouping multiple bits together. • **Size hierarchy from bottom up**: 1 bit → 1 nibble (4 bits) → 1 byte (8 bits) → 1 KB (8,192 bits) — the bit sits at the absolute base of this hierarchy and cannot be subdivided further in classical computing. • In quantum computing, the qubit can exist in superposition of 0 and 1 simultaneously, but in classical digital systems the bit remains the irreducible smallest unit of information. • 💡 Option A (Byte) is wrong because 1 byte = 8 bits, making it 8 times larger than a single bit; Option C (Nibble) is wrong because 1 nibble = 4 bits, four times larger than one bit; Option D (Kilobyte) is wrong because 1 KB = 8,192 bits, thousands of times larger than one bit.

Correct Answer: B. 8 bits

• **8 bits** = One byte is universally defined as exactly 8 bits; this standard has held consistent across all modern computer architectures since IBM established it with the System/360 in 1964, and it remains the foundation of digital encoding today. • **Encoding capacity** — With 8 bits, a single byte can represent 2^8 = 256 distinct values (0–255), which is sufficient for the entire ASCII character set and serves as the building block for UTF-8 encoding of text in all languages. • Before the 8-bit standard, early machines used 6-bit or 7-bit bytes, but 8 bits became universal because it aligned perfectly with ASCII requirements and proved optimal for binary arithmetic circuits. • 💡 Option A (4 bits) is wrong because 4 bits define a nibble, not a byte; Option C (16 bits) is wrong because 16 bits equal two bytes, forming a "word" on 16-bit processor architectures; Option D (32 bits) is wrong because 32 bits equal four bytes, the size of a 32-bit integer data type.

Correct Answer: C. 1 Kilobyte

• **1 Kilobyte** = In binary computing, 1,024 bytes equal exactly one Kilobyte because 1,024 = 2^10 — the nearest power of 2 to the decimal value 1,000, which is why the metric prefix "kilo" was adopted despite the slight difference. • **IEC clarification** — To eliminate ambiguity, the International Electrotechnical Commission defined "Kibibyte" (KiB) = 1,024 bytes and reserved "Kilobyte" (KB) for exactly 1,000 bytes; in everyday computing, however, KB almost always means 1,024 bytes. • A 1.44 MB floppy disk held 1,474,560 bytes — about 1,440 KB — illustrating how the Kilobyte was the natural unit for the media storage of the 1980s and 90s. • 💡 Option A (1 Megabyte) is wrong because 1 MB = 1,024 KB = 1,048,576 bytes, far more than 1,024; Option B (1 Gigabyte) is wrong because 1 GB = 1,073,741,824 bytes, enormously larger than 1,024 bytes; Option D (1 Nibble) is wrong because a nibble is only 4 bits, not 1,024 bytes.

Correct Answer: C. 1 Megabyte

• **1 Megabyte** = One Megabyte (MB) is equal to exactly 1,024 Kilobytes, because the memory hierarchy follows powers of 2 — 1 KB = 2^10 bytes, so 1 MB = 2^20 bytes = 1,048,576 bytes total. • **Historical significance** — Software in the MS-DOS and early Windows era was distributed on floppy disks of 720 KB to 1.44 MB, making the Megabyte the standard measure of software size throughout the 1980s and 1990s. • Today a single high-resolution smartphone photo can exceed 5 MB, showing how computing has grown far beyond the Megabyte scale for everyday media files. • 💡 Option A (1 Gigabyte) is wrong because 1 GB = 1,024 MB, making GB the larger unit rather than being equal to 1,024 KB; Option B (1 Terabyte) is wrong because 1 TB = 1,024 GB = 1,048,576 MB; Option D (1 Petabyte) is wrong because 1 PB = 1,024 TB, an astronomically larger unit than what 1,024 KB describes.

Correct Answer: B. 4 bits

• **4 bits** = A nibble is defined as a group of exactly four bits — half of one byte — and can represent 2^4 = 16 distinct values (0–15), mapping directly to the 16 hexadecimal digits 0 through F. • **Hexadecimal connection** — Because one nibble equals one hex digit, a single byte is always expressed as exactly two hexadecimal characters (e.g., byte value 255 = 0xFF = nibble 1111 + nibble 1111), making nibbles central to low-level programming and memory inspection. • The word "nibble" is a playful computing term derived from "byte" — if a byte is a full bite of data, a nibble is half a bite, reflecting the programmer humor woven into computing terminology. • 💡 Option A (2 bits) is wrong because 2 bits form a "crumb" or "dibit", a lesser-known unit smaller than a nibble; Option C (8 bits) is wrong because 8 bits form a full byte, twice the size of a nibble; Option D (10 bits) is wrong because no standard memory unit uses a 10-bit grouping.

Correct Answer: B. 1024 MB

One Gigabyte is equal to 1024 Megabytes in the binary measurement system. It represents over one billion bytes of data storage. Modern hard drives are typically measured in Gigabytes or Terabytes.

Correct Answer: A. Bit < Nibble < Byte < KB

A bit is the smallest, followed by a nibble (4 bits), then a byte (8 bits). The Kilobyte (1024 bytes) is the largest among these four choices. This hierarchy is fundamental to understanding computer data storage.

Correct Answer: C. 1024 GB

One Terabyte is equivalent to 1024 Gigabytes. This unit is commonly used to describe the capacity of high-volume storage devices. It represents roughly one trillion bytes of information.

Correct Answer: A. Petabyte

The Petabyte (PB) is the next unit in the hierarchy after the Terabyte. It is equal to 1024 Terabytes or approximately one quadrillion bytes. Large data centers often measure their total capacity in Petabytes.

Correct Answer: B. 1,048,576 bytes

By multiplying 1024 bytes (1 KB) by 1024 (KB in an MB), we get 1,048,576 bytes. This is the precise number of bytes in one binary Megabyte. Manufacturers sometimes use 1,000,000 as a decimal approximation.