jim bell <jimbell@pacifier.com> writes:
Be careful writing code - sometimes a byte is -128 to 127 instead of 0 to 25 Also, there are machines (mostly old kinky ones) that use bytes of sizes other than 8 bits.
No, Bill, a "byte" has ALWAYS been 8-bits. One of the main reasons the term "byte" was invented was because the term "word" (as in, "word length") varied for different computers, especially in the 1960's. (In fact, many computers of that era used word lengths other than 8, 16, 32, 64 bits, as surprising as this may sound to the current crop of PC and Mac afficionados.) This made it inconvenient to talk about memory capacities unless you were referring to the same machine. The solution was to invent a new term, "byte," which conviently had about the same size as an ASCII character and was always 8 bits.
I used to hack a CDC Cyber box designed by Seymour Cray before he started his oen company. It had the following curious features: 1 word = 10 _bytes_ = 60 bits 1 _byte_ = 6 bits Out of respect for Jim, I dug up the dox, which say: "On the 6600, the basic bit groupings are 6, 12, 15 and 30 bits". The dox consistently refer to the 6-bit chunks as "characters", never bytes. However I've heard people refer to 6 bits as bytes and to 3 bits (an octal digit) as nybbles. Naturally, the character set had only 64 symbols - no lowercase letters. Both integers and reals were 60 bits. Addresses in the instructions were 15 bits, but that was an address of a 60-bit word. Negative numbers were represented with one's compliment (i.e. -X = NOT X). Hence there were two zeroes: positive and negative. I believe BESM-6 also had 6-bit bytes. I have the dox for it someplace (in Russian) but can't find them offhand. Moral: it's not necessarily redundant to say '8-bit byte'. --- Dr. Dimitri Vulis Brighton Beach Boardwalk BBS, Forest Hills, N.Y.: +1-718-261-2013, 14.4Kbps