Crumb

/krəm/

noun — “barely enough information to leave a trail.”

Crumb is hacker jargon for a quantity of 2 binary digits—that is, 2 bits. It occupies an awkward but oddly charming place between a single Bit and a nybble, making it larger than the smallest practical unit while still feeling too tiny to deserve serious measurement.

Numerically:

1 crumb = 2 bits

= 1/2 nybble
= 1/4 byte

Since each bit has two possible values, a crumb can encode exactly four states:

00 = 0
01 = 1
10 = 2
11 = 3

That might not seem like much until you realize how often four states are enough.

A crumb can express tiny categories:

// compact state storage

00 = off
01 = standby
10 = active
11 = error

Or directional values:

// movement

00 = north
01 = east
10 = south
11 = west

Or permissions:

// two-bit permission

00 = none
01 = read
10 = write
11 = read/write

In other words, despite sounding ridiculous, two-bit quantities appear constantly in real systems.

The term itself follows the familiar hacker tradition of turning information units into food. If a Byte is a bite and a nybble is a smaller snack, then something even smaller naturally becomes a crumb—not enough to eat, but enough to notice.

The hierarchy becomes increasingly suspicious as it grows:

1 bit    → bit
2 bits   → crumb
4 bits   → nybble
8 bits   → byte
16 bits  → playte
32 bits  → dynner

Unlike byte, however, crumb never escaped into standard terminology. It remained mostly within hacker humor and experimental jargon. Even among technical people, saying “store that in a crumb” usually earns either appreciation or concern.

There is also something unintentionally elegant about the name. A crumb is small, incomplete, and rarely useful by itself—but gather enough crumbs together and suddenly you have structure. That mirrors digital systems surprisingly well: enormous software stacks are ultimately assembled from countless tiny decisions represented by groups of bits.

Historically, machines with unusual memory layouts and compressed storage formats occasionally encouraged people to think at these smaller granularities. Modern systems tend to abstract that away, but underneath the abstractions, crumbs still quietly exist.

Considered silly... but not entirely useless.

Syn. tayste.

See quad, tayste, Bit, nybble, Byte