When you think about the dawn of modern computers, you often think about the work done in the UK and the US. But Australia had an early computer scene, too, and [State of Electronics] has done a series of videos about the history of computers down under. The latest episode talks about SILLIAC, a computer similar to ILLIAC built for the University of Sydney in the late 1950s.
How many racks does your computer fill up? SILLIAC had quite a few.
This episode joins earlier episodes about CSIRAC, and WREDAC. The series starts with the CSIR Mark I, which was the first computer in the southern hemisphere.

The -AC computers have a long history. While you often hear statements like, “…in the old days, a computer like this would fill a room,” SILLIAC, in fact, filled three rooms. The three meters of cabinets were in one room, the power supply in another. The third room? Air conditioning. A lot of tubes (valves, in Australia at the time) generate a lot of heat.

It is hard to put an exact cost on SILLIAC, but the original estimate was about AU£35,200. That sounds modest, but at the time, you could buy about ten suburban homes near Sydney for that price. Like most projects, the cost rose, and completion depended on a larger donation from a horse race. At the end, the cost was about AU£75,000!

SILLIAC had a reputation of being more reliable than some other computers based on the same design. That was probably because most computers use 6J6 tubes, but SILLIAC used 2C51 devices. Bell Labs created the 2C51 for use in undersea cables. Of course, they were also about six times the cost of a 6J6.

The computer did important work until 1968. It was, sadly, dismantled, but pieces of it are hanging around the Powerhouse Museum and at the University as display items.

This series is a great look at what was happening in the computer world south of the equator during these days. While SILLIAC is fascinating, you might want to start with episode 1. Supercomputers have come a long way.

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hackaday.com/2025/04/03/austra…

All the news that was fit to print. Image via Wikipedia
In the 1982 movie Fast Times At Ridgemont High, a classroom of students receives a set of paperwork to pass backward. Nearly every student in the room takes a big whiff of their sheet before setting it down. If you know, you know, I guess, but if you don’t, keep reading.

Those often purple-inked papers were fresh from the ditto machine, or spirit duplicator. Legend has it that not only did they smell good when they were still wet, inhaling the volatile organic compounds within would make the sniffer just a little bit lightheaded. But the spirit duplicator didn’t use ghosts, it used either methanol (wood alcohol), isopropyl, or, if you were loaded, ethyl alcohol.

Invented in 1923 by Wilhelm Ritzerfeld, ditto machines were popular among schools, churches, and clubs for making copies of worksheets, fliers, and so on before the modern copy machine became widespread in the 1980s. Other early duplicating machines include the mimeograph, the hectograph, and the cyclostyle.

Getting A Handle On Duplication

To use the ditto machine, one would first make a master copy using a special sheet of paper with a special type of waxy ink on the back that dissolves in alcohol. These types of sheets are still around today, in a way — if you’ve ever gotten a tattoo, you know that they don’t usually just freehand it; the artist will draw out your design on special paper that they can then use to lay down a temporary tattoo on your freshly-shaved skin before going for it.
Image via Wikipedia
But don’t get too excited; tattoo transfer sheets aren’t compatible with ditto machines for a number of reasons. As I mentioned, ditto sheets use alcohol to transfer the ink, and tattoo sheets use heat and pressure. They’re too thin for the mechanics of the ditto machine’s drum, anyway.

So once you’ve typed or drawn up your master sheet, you’d mount it on the drum of the ditto machine. Then, with a big crank handle, you’d roll the drum over sheet after sheet until you had what you needed. The average master could make roughly 50 to 500 copies depending a number of factors.

The rise of higher-quality master sheets is largely responsible for this wide range, but there are other factors at play, like the color that gets used. Purple was made from a dye called aniline purple and lasted longest on paper, although there was also green, red, and black. You see a lot of purple dittos because of its vibrancy and the fact that it was highly soluble in alcohol.

The type of paper entered into the equation as well: absorbent paper like newsprint would make fewer copies than smoother, less porous bond paper. And, as you might imagine, dense text and images used more ink and would wear out the master faster.

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As with many paper-based things from decades ago, the durability of dittoes is not so great. They will fade gradually when exposed to UV light. Although there is no citation, Wikipedia claims that the average ditto would fade in direct sunlight after about a month. It goes on to assume that most ditto machine users printed onto low-quality paper and will eventually “yellow and degrade due to residual acid in the untreated pulp”.

Not a Mimeograph

It’s worth mentioning that mimeographs are not quite the same thing as ditto machines. For one thing, ditto machines were often hand cranked, and many mimeographs were motorized. Interestingly enough, the mimeograph predates the spirit duplicator, having been patented on August 8, 1876 by Thomas Edison and popularized by the A.B. Dick Company in the 1880s.

Also known as stencil duplicators, mimeographs were a competing technology that used ink and stencils to produce 50 to several thousand copies. A special stencil sheet bearing a wax coating would be typed on a regular typewriter with the ribbon disengaged and the machine set to this mode, and/or written or drawn upon using a special stylus and lettering guides.

The stencil sheet would then be fed into the machine, which had a large drum with an ink pad. The mimeograph would then squish ink through the stencil and onto the paper. You can see all this and more in the video below, which illustrates just how much of an art this whole process was compared to makin’ copies today.

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Mimeographs were largely done in black, but color could be done “easily”, as the video demonstrates. You basically had to hand paint the colors onto your stencil. It doesn’t seem as though changing out the giant ink pad was an option. Unlike dittoes, mimeographs required better paper, so they should last longer in theory.

Before You Run Off

Duplication for the common man is as important as the printing press itself. While today you might just set the printer to provide the number of copies you need, the history of duplication shows that we’ve come a long way in terms of effort on the user’s end. Keep this in mind the next time you want to go Office Space on it.

hackaday.com/2025/04/03/ditto-…

Eh sì amici miei, non lo sapevate, ma siamo i peggiori.

Siamo delle bruttissime persone. Orribili. Così raccapriccianti e temibili da farci definire "i peggiori" da parte di Trump.

Peggiori perché?

Perché abbiamo osato dire che, se ci avesse imposto dei dazi, li avremmo messi a nostra volta. E così, come se niente fosse, Trump ci ha messi tra i peggiori, affibbiandoci dazi del 20%, e ci è andata pure bene rispetto alla Cina che ne subirà il 30%.

Quindi, ricapitoliamo: è come se io dicessi a qualcuno che sto per dargli un pugno. Questo mi risponde che se glielo do me ne darà uno anche lui, e decido che l'altro è violento. E così, per difendermi, gli do un pugno per primo.
Non fa una grinza, che ne dite?

Il problema è che in questa sagra delle post-verità che è diventato il mondo, si rischia che chi vedrà la cosa a posteriori pensi davvero che il violento non sarei io, ma l'altro.

Comunque io, se fossi in voi, mi vergognerei un po'. Prendercela così tanto con un pover'uomo anziano (Trump) che, evidentemente, ha ormai varie rotelle fuori posto.

Cioè, non vi fate un po' schifo da soli, quando vi guardate allo specchio? Da oggi, io sì, perché sono tra i peggiori. Mica i terroristi, o chi invade un Paese straniero.

Noi, i peggiori.

#trump #dazi #tariffs #boycottusa #USA #tariffswar #guerradeidazi #Politica

La biografia definitiva di Robert Johnson. La mia recensione su Free Zone Magazine.
#libri #biografie #blues #RobertJohnson

Bruce Conforth, Gayle Dean Wardlow - Il diavolo, probabilmente. Vita di Robert Johnson | FREE ZONE MAGAZINE freezonemagazine.com/articoli/…

Bruce Conforth, Gayle Dean Wardlow - Il diavolo, probabilmente. Vita di Robert Johnson | FREE ZONE MAGAZINE

Robert Johnson è un bluesman fondamentale, e questo libro fa pulizia degli aspetti mitologici per approfondire il musicista.

^{FREE ZONE MAGAZINE}

Siamo ormai nel 2025 ed è ora di aggiornare anche i teoremi scientifici più blasonati.

Il gatto di Schroedinger non è più attuale; passiamo al foglietto illustrativo di Schroedinger.

Si trova sia a destra che a sinistra nella confezione del farmaco, finché non apri la scatola: allora sarai certo che si trova nel lato che hai aperto.

In sostanza: non importa quante volte giri la scatola o in che senso, il foglietto sarà sempre nella posizione migliore per romperti i coglioni.

#Teorema #scienza #humour #medicine #farmaci #schroedinger #gattodischrodinger #bugiardino #bigpharma