Actually, in this case 32 bit and 64 bit refer not to the natural word size, but to the address size. i.e. a 32 bit machine uses a 32 bit address for memory, and cannot address as much memory as a 64 bit machine, using 64 bit addresses, can. In the case of the IBM mainframe computers, the natural word used to be 32 bits, but they were 31 bit machines, as the top bit of the word was reserved for something other than an address bit. The new mainframes are 64 bit machines, using all 64 bits of an address to address memory. They're still 32 bit words though; they just happen now to use two of them for an address. (Actually, the smallest thing the mainframe would deal with for a long time (early 1980's forward) has been 64 bits, or a double-word. The main change has been the use of larger addresses.) -- Robert P. Nix Mayo Foundation RO-OC-1-13 (new loc) 200 First Street SW 507-284-0844 Rochester, MN 55905 ----- "In theory, theory and practice are the same, but in practice, theory and practice are different." -----Original Message----- From: fedora-list-bounces@xxxxxxxxxx [mailto:fedora-list-bounces@xxxxxxxxxx] On Behalf Of Mike McCarty Sent: Wednesday, November 16, 2005 12:21 PM To: For users of Fedora Core releases Subject: Re: short answer to technical question? Gerhard Magnus wrote: > Hello All, > > I don't know if there's a short answer to this... but what do "32 bit" > and "64 bit" refer to and how can I tell which applies to my computer? > > Jerry Modern PC style computers all are binary. (Most calculators are decimal.) The word "bit" is a contraction of "binary digit". All computers have a natural word size, measured in digits. This is the size of word which the computer can use without special software. If the natural size of a computer word is 8 bits, then it is called an 8 bit computer. Examples are the 8080, Z80, 68HC11, and so on. Computers whose natural word size is 16 bits are the 8086, Z8000, 68000, etc. The 80386 and later 80x86 machines up through the Pentium class machines were all 32 bit machines. Now, some machines have a natural word size of 64 bits. The only way to tell is to know what the processor chip is. Mike -- p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);} This message made from 100% recycled bits. You have found the bank of Larn. I can explain it for you, but I can't understand it for you. I speak only for myself, and I am unanimous in that! -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list
