<file format, algorithm> A file format using 64 ASCII characters to encode the six bit binary data values 0-63. To convert data to base 64, the first byte is placed in the most significant eight bits of a 24-bit buffer, the next in the middle eight, and the third in the least significant eight bits. If there a fewer than three bytes to encode, the corresponding buffer bits will be zero. The buffer is then used, six bits at a time, most significant first, as indices into the string "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" and the indicated character output. If there were only one or two input bytes, the output is padded with two or one "=" characters respectively. This prevents extra bits being added to the reconstructed data. The process then repeats on the remaining input data. Base 64 is used when transmitting binary data through text-only media such as electronic mail, and has largely replaced the older uuencode encoding. (2004-07-17)

In computer programming, Base64 is a group of binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits.

64 was a Russian chess magazine and draughts publication, published in Moscow. Its name referred to the number of squares on a chessboard.

Commodore 64 [Additional explanations: computer] (Reference: Commodore)

Commodore 64

<computer> (C64) An 8-bit Commodore Business Machines personal computer released around September 1981. Prototypes were (apparently) made before Christmas 1980 (and shown at some computer fair). The CPU was a 6510 from MOS Technologies (who were a wholly owned subsiduary of Commodore at this time(?)). The C64 had 64 kilobytes of RAM as standard and a 40-column text, 320x200 pixel display generating composite video, usually connected to a television. DMA-based memory expanders for the C64 (and C128) allowed 128, 256, and 512 kb of RAM. Several third party manufacturers produce accelerators and RAM expanders for the C64 and C128. (Some, risking a holy war, compare this to putting a brick on roller-skates). Such accelerators come in speeds up to 20MHz (20 times the original) and RAM expanders to 16MB. The C64's 1541 5.25 floppy disk drive had a 6502 processor as a disk controller. See also Commodore 65. ["Assembly language programming with the Commodore 64", Marvin L. De Jong]. (1996-06-05)

<architecture> A term describing a computer architecture based around an ALU, registers and data bus which are 64 bits wide. 64-bit processors were quite common in 1996, e.g. Digital Alpha, versions of Sun SPARC, MIPS, IBM AS/4000. the PowerPC and Intel were expected to move to 64 bits at their next generation - PPC 620 and Intel P7. A 64-bit address bus allows the processor to address 18 million gigabytes as opposed to the mere 4 gigabytes allowed with 32 bits. There were in 1996 already hard disks which can hold over 4GB. Floating point calculations can also be more accurate. A 64-bit OS is needed as well to take advantage of the CPU. In 1996 there were only a few 64-bit operating systems, including OS/400, Digital Unix, Solaris (partialy). A 32-bit OS can run on a 64-bit CPU. (2004-05-12)

The Arado Ar 64 was a single-seat biplane fighter, developed in the late 1920s. It was among the first fighters produced when Germany abandoned the restrictions of the Treaty of Versailles and began rearming.

In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size.

This article describes the processor, memory, and other components of the 1996 Nintendo 64 home video game console.