# Tag Info

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

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,...

40

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 takes a fair bit of logic to implement. Binary is positional. That means that a 1 which is 4 places ...

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 ...

22

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-...

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

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

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 ...

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. ...

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

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 ...

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 Zuseâ€”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 ...

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 ...

4

Well, there is no definite answer, as an electric or even electronic adder would be useless before other machinery/circuitry would be available to feed it and take results fast enough to make it worthwhile. This wasn't the case way into the 40s as up to them (electro) mechanical adders were not only sufficient well developed, but also quite capable to peep ...

3

It's possible to try both CTSS and ITS yourself. Both operating systems run on emulators. As for differences, Tom Knight, one of the ITS creators, wrote: I would actually say that the main influence of CTSS on ITS was a demonstration of just what it was that we didn't want to do. See more here: https://github.com/PDP-10/its/issues/1588

3

Actually, mechanical translation by Google works remarkably well. I found that I needed to first copy the text to my text editor (emacs, in my case) in order to convert the umlauts into proper Unicode characters, but then I just pasted the paragraphs one at a time into Google, and got the following, which is quite idiomatic. I have not touched up the results ...

3

Why didn't the Whirlwind I use a high persistence crt or something ? Because then no dynamic display, like the ball shown at minute 11:0, could have be done? On this video Whirlwind I at 1:48, you can see the text being diplayed, it is only very briefly visible, apparently they would take a film picture and some hours ( or a day ) later see the results on ...

2

Intro I already added an answer, but this time I want to expand on the idea more forcefully. First, let me say that I think this question perhaps better belongs on CS. It's more about philosophy and theory than it is about the Jaquard Loom, per se. Even so, let's run with it and see how far we get. New Claim We all agree that a given bit string might ...

2

Program code is a specific type of data. So the question is really: What is it that distinguishes code data from other forms of data?. Non-code data is a representation of state. Code data is a representation of a process for manipulating data. Data states remain stable until they are acted upon over time according to the instructions in the code data. ...

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