# Tag Info

45

I will just explain what a bit is. It's a binary digit. 0 is numerically zero, 1 is numerically one. If you want to add 1 and 1, in binary it overflows. the result is 0, and a carry out. As you understand, other arithmetic operations can be done on bits. They take a fair bit of logic to implement. Binary is positional. That means that a 1 which is 4 places ...

29

Quibbling about the right meaning of "bit" aside, some advantages of the 2-of-7 biquinary representation are: Simpler circuits. In a quinary adder circuit, the output of each of the 5 output lines becomes just a 5-way OR of binary ANDs of input lines. To implement this with primitive logic building blocks such as resistor-transistor-logic (or its vacuum-...

17

From a modern chip design perspective, the design of bi-quinary adders is quite simple. The addend inputs are each composed of two 1-hot signals, and the sum output is two 1-hot signals as well. This is by the nature of bi-quinary, where the quinary part is 1-hot by definition and the binary part is a 2-bit signal that is 1-hot by convention, being either ...

11

Really early computers like the Mark I and ENIAC didn't have enough memory to attempt to handle text; also the use-case was mostly calculations. A number of decimal IBM computers used characters (with 5 or 6 usable bits) as the basic unit, and decimal digits were just a special usage of those characters: The IBM 1401 computer, and its compatible successors ...

5

Storing a one-of-two selection using vacuum tube technology doesn't require one valve (combination of an anode, cathode, and one or more grids); it requires two. Thus, holding four bits would require eight valves. Because a one-of-five selection can be held with five tubes, holding a one-of-five selection plus a bit will require seven tubes. Note that from ...

5

This isn't intended as an answer per se, but I want to provide some support for OmarL's explanation by quoting official documentation for the machine, which speaks of binary values as units of information rather than as digits of a base-2 number. Here is how the IBM 650 Customer Engineering Manual of Instruction describes the machine's representation of ...

1

Singer made a series of retail systems which were taken over by ICL and rebranded. The ICL System 10 used 6-bit bytes for decimal and character data. The ICL System 25 used 8-bit bytes, which were used for full ASCII text, and in arithmetic operations as packed decimal (two 4-bit nibbles holding 0x00 to 0x09). Singer were fairly adventurous. They made sewing ...

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