4 ms·
Just seems wierd. A 2 byte day count would give a huge range and use 2 bytes for the full date Vs 3 bytes for a BCD yymmdd representation.
by MichaelGG 9y ago
Just seems wierd. A 2 byte day count would give a huge range and use 2 bytes for the full date Vs 3 bytes for a BCD yymmdd representation.
- zaxomi 9y agoThere are a lot of weird things... You are assuming 8 bits per byte, but a byte can be any number of bits. With two bytes of 7 bits each, the range is only about 40 years. Is is also impractical when the storing media is punch-cards, and the systems adder unit only counts in binary coded decimal.
- wpietri 9y agoBut then you need special code to decode that. Code that you have to write yourself or borrow and include in your program. Remember, no shared libraries. And it means extra CPU time you have to display a date. Whereas BCD has special hardware support. It means that data interchange is now much more complicated too. How do you get everybody to agree on the same 2-byte representation for dates? This is the 1960s, so you can't just email them. You have to have somebody type up a letter and mail it. Or if you want to get on the phone, a 3-minute international call will cost $12, which is about $100 in 2017 dollars. Plus then you can't look at a hex dump or a punch card or front panel lights and see the date, so now you've made debugging much harder.