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Bits or Bytes?

  5 minute read.

Last Modified 2023-03-31 13:47 EDT

Which is it, bit or byte? And what is the difference between a bit or a byte?

Both bit and byte are basic measurements for computerized data but they represent different measurements.

A bit is the smallest unit of measure for computerized storage, and when combined with a time measurement such as seconds, becomes the common basis for determining how fast raw data bits transfer across a network, as in bits per second (bps). It is the basic unit of measurement for network bandwidth. A bit is the raw data unit, and is either a zero (0) or one (1). A bit is represented in measurements as the lower case b as it kilobits (kbs), megabits (Mbs), gigabits (Gbs), etc. When discussing the rate of speed as in bits per second (b/s or bps) you see measurements as Kbps for kilobits/second, Mbps for megabits/second, Gbps for gigabits/second, etc.

A byte is made up of eight bits and is the basic measurement for estimating storage capacity of drives or other storage media. When grouped in twos (2s), fours (4s), or eights (8s) they form words or groups of bytes, with the machine used determining the grouping size of these words. The byte is the most basic unit of measure on a machine (or device such as a hard disk drive). Bytes contain 256 permutations of eight binary digits to represent the ASCII characters, such as the letter upper or lower case “A” or an @ or other symbol. A byte can represent any number between zero and 255. Think of a byte as representing the characters stored in them. A byte is represented by the upper case B as in kilobytes (KBs), megabytes (MBs), gigabytes (GBs). A byte is the basic measurement to estimate how long it takes to exchange (store/retrieve) locally-stored information. Or for the store/retrieve rate, KBps for kilobytes/second, MBps for megabytes/second, GBps for gigabytes/second, etc. As a provider of storage, TrueNAS represents storage measures in bytes.

For TrueNAS, which is correct and do they represent the same measurement?

No they are not the same measurement. It takes eight (8) bits to make a byte, and the bit is used to estimate the speed at which data transmits across a network. The network capacity, or bandwidth, determines how fast the raw data bits transmit across it. TrueNAS refers to bits when discussing the network transmission speed of data from TrueNAS storage to another system across a network. Network provider capacity and other network related devices such as network interface cards (NICs) can either determine or influence the network transmission speeds.

A byte, or eight bits of raw data formed into words to represent characters, is the unit of measure to estimate local storage capacity (such as on a hard drive or other storage device) and measures the rate computerized data is stored or retrieved on a local storage device or system. TrueNAS, like other storage providers, uses bytes to quantify the storage capacity it provides based on the system hardware platforms it provides to customers.

To B or not to b?

Lower case b denotes bits. Lower case b because a bit is smaller than a byte.

Upper case B denotes bytes. Upper case B because the byte is larger and it takes eight bits to make a byte.

Tebibytes (TiB) verses terabytes (TB)?

What is the difference between tebibytes (TiB) and terabytes (TB) measurements? It comes down to math, the meaning of the prefixes, and changes in the computer industry.

The original standard, set by the International System of Units (SI), is based on metric system measurements of multiples where kilo has come to represent 1000, mega a million, giga a billion, tera a trillion, and peta a quadrillion, etc.

The International Electrotechnical Commission (IEC) also uses the same prefix syllable of the name but adds the second syllable “bi” (pronounced bee). These are not part of the International System of Units (SI) but were derived from the SI positive powers of ten. The “bi” recalls the word binary. The lower case i in the measurement represents the word binary, so a tebibyte (TiB) is the unit of measure for a trillion, pebibyte for a quadrillion, etc.

It comes down to math and the actual equivalent of 2^10^ which nearly equals 1000 but is actually 1024. Most people accept kilo to represent 1000. As the computer industry grew and change, the measurements of capacity grew along with it making gigabyte and terabyte more common and available but these are not based on binary trees. IEC developed a standard to address the discrepancy between binary arithmetic and decimal arithmetic. While most people understand megabyte to represent a million, computer manufacturers use megabyte to mean 2^20^ or 1,048,576 bytes when discussing memory but use 1,000,000 bytes when talking about computer storage. This can lead to confusion in the consumer mind when trying to sort out available capacity in their computer systems.

The Institute of Electrical and Electronics Engineers (IEEE) standards board decided that IEEE will use the conventional SI prefixes (mega, kilo, tera, peta, etc.) to mean, 1,000,000 for mega (and so forth). The base-two definition may be used by computer manufacturers on a case-by-case basis, and until prefixes for binary multiples are adopted by an appropriate standards body.

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