46

Very simple: Because there was room for an address and it improves performance a lot. Or as the manual puts it: It is important, however, for the programmer to realize that the simplest method of programming (using sequential drum location for succeeding instructions) causes the machine to waste a large amount of time waiting and searching. To start with,...


44

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 ...


44

Do the holes in Jacquard loom punched cards represent input data or program code? yes. Let me tell you a story. Somebody I used to work with many years ago was flying into the USA (or it might have been Britain from the USA) with some half inch tapes containing the source code for a Cobol program. Because he was carrying the tapes separately to his luggage,...


28

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-...


25

Quoting the 50th anniversary page on the topic, In parallel to the Meg project it was decided to build a relatively small and economic computer. When design was started in 1952 it was clear that the project could provide valuable experience in the use of the recently introduced transistors. It was built even though the germanium point transistors were ...


20

The technical differences are large when compared to the technical similarities. CTSS was built for a modified IBM 7094 system while ITS was built for the DEC PDP-6 (later PDP-10). Both of these machines were organized around 36 bit words, but the similarity tails off after that. Both machines lacked a hardware page map, and did not attempt to provide ...


17

Program code for modern CPUs, in practice, consists of opcodes which tell the CPU what operation to perform, and operands which provide data to operate on. In RISC CPUs these are necessarily both encoded into the same instruction word, while in CISC CPUs the two usually live in separate bytes, with the operands following each opcode. However there are ...


15

No, this has nothing to do with any networks; the "INT" stands for "integrator." That panel and the adjacent one to the right are the interface to an integrator/memory module: Integrators in analogue computers are used to measure quantity over time, basically a sort of sum function. You can find more pictures of the modules on The Analog Computer Museum's ...


15

All code is data. But not all data is code. For example, you can take a digital photo and the numbers represent light intensity across a 2D rectangle. Nobody would dispute that this is data but not code. Code is a special kind of data which controls behaviour. ... but it's not that simple. Arguably the digital photo controls the behaviour of whatever ...


14

[Preface: this is about a very early architecture, defined way before and completely independently of today's canon, formed by IBM's /360. When reading, it might be useful to take terms used at their face value, and strip all the semantic baggage that goes with them when talking about today's architectures.] The Zuse Z22 is in may ways unique (*1), not just ...


12

Horst Zuse (Konrad Zuse's son, a computer science professor by trade) has a homepage where he supplies (and sells) various pieces of information, booklets and CDs and DVDs about his father's work. The Z4 had two floating point registers, R1 and R2, that were used for calculations. Monadic operations operated on R1 only, dyadic operations on R1 and R2. ...


12

The notation 3.2n looks to me like it means 3 x 2n rather than (3 point 2)n. So the question is whether data lengths should be based on a 6-bit unit or some 'binary' size, in practice 8 bits. The dominant character size at the time was 6 bits (with 7-bit ASCII just emerging). A 36-bit word length was also common, and was in fact the word size for the ...


11

For most parts it's code. Well, code is a quite sloppy term, it covers a huge list of uses, from card scratching to encryption. So more correctly, it's a program (*1), as it defines a sequence of action to be taken by the machine - interpreted when the loom runs the cards. If at all, then thread is data. It is input from spools, processed by the loom ...


11

You can have a look at how simh, which emulates quite a few computer systems that had punch cards, paper tape, magnetic tape, harddisks, floppy disks, printer and terminals, handle it. Basically most kind of storage mediums (including paper tape) are mapped to a file. The printer is also mapped to file. Terminals are mapped to some kind of interface you can ...


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 ...


10

If your primary memory is not random access, in the sense that at any instant some addressed words will take longer than others to be read, then you can potentially improve performance by having each instruction specify where the next instruction is located. The programmer is then coerced to figuring out where that next instruction ought to be. This ...


9

Yes, it WAS due to the fact that with a rotating drum memory, you wanted the next instruction to be at a location that was just about to come under the read/write heads rather than in the next sequential location, where it could take a full revolution of the drum to be able to read the instruction. All was not lost for the programmer, however. The 650 came ...


8

Note that 3.2 is the square root of 10 rounded up to the closest value with one digit after the decimal. Thus, every other data length module will be slightly greater than a power of 10. Apparently there was an expectation that data block lengths will be typically close to powers of 10, achieving good capacity utilization, while providing acceptable ...


7

The first recorded use of relays in process control computing is in a patent granted to John Saxby in 1856. A brief description is given here. They were used to control railway signalling. The 'interlocking' superseded the mechanical interlocking systems used in Victorian signal boxes. It was only permitted to set a signal to "Proceed" if the track ...


7

I think the other answers cover the topic pretty well, but allow me to ask a related question as food for thought: is the music roll of a player piano code or data? On the one hand, the piano just sits there and does nothing without the roll, suggesting that it's "code". On the other, the roll is morally equivalent to sheet music that a human musician ...


6

The Jacquard loom predates the computer by a long time. As such, the distinction is a bit like asking whether or not a horse runs on diesel or petrol; whatever distinction you're trying to make by applying terminology from a different technology isn't likely to be useful or meaningful. The distinction between code and data is mostly a relic of Von Neumann ...


6

Switches are intended for just turning ON or OFF the power supply by either closing or opening the circuit. Not really. Switches in process control are intended to sense a state. That the result and its use can be combined is rather a nice shortcut. Already early on, contactors were used to control power machienery with lower voltage circuits, itself ...


5

Konrad Zuse—the first relay computer The Z4 made use of a unit called a Planfertigungsteil (program construction unit),which was used to produce punch tapes, containing instructions for the Z4 in a very easy way. For this reason, it was possible to learn the programming of the Z4 in as little as three hours. The Z4 had a large instruction set in order to ...


5

How many logic gates did the IBM 650 have? It's a rather useless question. When is a gate a gate? Is a wired-OR a gate? Does a 38-input-OR, used to create a zero condition count as much as a two-input? Using a gate count does, if at all, only make sense for machines only build from diskrete gates. I'm used to measuring the complexity of a CPU by ...


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 ...


5

Not too sure about resources, actually. But, I can walk you through the logic I used when I wrote an (unpublished) emulator for BESK, a machine that had paper tape for input, either in "5-bit teletype code" mode or "4-bit binary number" (using one channel as a "there's data" indicator) and for output had a printer (well, an ...


5

Peter Onion's Elliott 803 emulator tries to replicate the experience of using an 803 in a 3D, almost VR, setting. Virtual paper tapes are used to load programs and data. Doug W. Jones's Punched Cards pages have more on how punched cards were used than almost anywhere else. The simh emulator uses Doug's punched card library for managing card inputs for ...


4

Maybe not the earliest, but early and important, and very elaborate uses: Automatic telephone exchanges. Strowger, 1891. Elevator control (early 20th century). Telegraphy, especially teleprinters (from the early 1900s). Railroad signalling, especially railroad safety (eg INDUSI, 1930s).


4

From what I know, and what the video supports, this is 'simply' an analogue computer. Analogue computers are not programmable in a sense like we use the term today. They are more like Construction Sets with predefined blocks and mounting plates. In this case like a highest quality Meccano-like set. Analogue computers work, as their name say, by building a ...


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