![]() Mechanical calculator… These calculators had a column of keys for each digit,Īnd operators were trained to use all their fingers when entering numbers, so Scientific and engineering calculation was the ten-digit, electrically powered, Prior to the introduction of computers, the state of the art in precision That there’s a great explanation in the Wikipedia article on 36-bit computing: why did mainframes use 36 bits?Īlso related to the 6-bit byte: a lot of mainframes used a 36-bit word size. Wanted? But it’s all I could find in a quick search. If you use a 32-bit word size? Why couldn’t you use 9 bits or 10 bits if you ![]() I don’t understand this comment at all – why does the exponent have to be 8 bits You to lose some of the information more rapidly than you would with binary Span, you had to adjust by 4 bits instead of by a single bit. Point, with the 32-bit word, you had to keep the exponent to just 8 bits forĮxponent sign, and to make that reasonable in terms of numeric range it could Would have given me a more rational floating point system, because in floating I wanted to make it 24 and 48 instead of 32 and 64, on the basis that this Here’s a quote from this interview from Gene Amdahl: I was curious about this comment that the 6-bit byte would be better for scientific computing. why was the 6-bit byte better for scientific computing? Says on page 7 that the Datapoint 2200 supported ASCII (7 bit) and EBCDIC (8 bit). ![]() This Datapoint 2200 manual from the Computer History Museum Represent letters as well as terminal control codes, so it makes sense for them ![]() Used in a computer terminal (the Datapoint 2200). It looks like the next important machine in 8-bit-byte history was the To go with the 8-bit byte, System/360 also introduced the EBCDIC encoding, which is an 8-bit character encoding. It makes sense that an 8-bit byte would be better for text processing: 2^6 isĦ4, so 6 bits wouldn’t be enough for lowercase letters, uppercase letters, and symbols. My most important technical decision in my IBM career was to go with the 8-bit byte for the 360.Īnd on the basis of I believe character processing was going to become important as opposed to decimal digits. So it came down to an executive decision and I decided for the 8-bit byte, Jerry’s proposal. … the six bit bytes really better for scientific computing and the 8-bit byte ones are really better for commercial computing and each one can be made to work for the other. Here’s a video interview with Fred Brooks (who managed the project) talking about why. This Wikipedia article says that the IBM System/360 introduced the 8-bit byte in 1964. Now let’s talk about some possible reasons that we use 8-bit bytes! reason 1: to fit the English alphabet in 1 byte So I’mĬonfused – is a word on x86 16 bits or 64 bits? Can it mean both, depending On x86 a word is 16 bits even though the registers are 64 bits. But according to section 4.1 (“Fundamental Data Types”) of the Intel architecture manual, Originally thought that the word size was the same as your register size (64īits on x86-64). The natural unit of data used by a particular processor design”). This for years, and the Wikipedia definition is incredibly vague (“a word is The word size is some multiple of the byte size.For example in a program on my machine 0x20aa87c68 might be the address of one byte, then 0x20aa87c69 is the address of the next byte. the byte size is the smallest unit you can address.What’s the difference between a byte and a word? My understanding is: what’s the difference between a byte and a word?įirst, this post talks about “bytes” and “words” a lot. Here are some potential reasons I found for the 8-bit byte. There aren’t any definitive answers in this post, but I asked on Mastodon and Not sure if we’d use a class field at all! The class field the same way if we could redesign DNS today without worrying about backwards compatibility. To me that’sĪ clear example of a historical accident – I can’t imagine that we’d define Possible values (“internet”, “chaos”, “hesiod”, “none”, and “any”). So we’re going to talk about some computer history.Īs an example of a historical accident: DNS has a class field which has 5 Reason for why a computer thing is the way it is today, or whether it’s mostlyĪ historical accident. Like reading about them), but I am always curious if there’s an essential I’m not super into computer history (I like to use computers a lot more than I 8 bits is objectively the Best Option for some reason, even if history had played out differently we would still use 8-bit bytes.It’s a historical accident, another size (like 4 or 6 or 16 bits) would work just as well.With any question like this, I think there are two options: One question I’ve gotten a few times is – why does the x86 architecture use 8-bit bytes? Why not I’ve been working on a zine about how computers represent thing in binary, and
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |