The familiar five volts standard from back in the TTL days always struck me as odd. Back when I was just a poor kid trying to cobble together my first circuits from the Forrest Mims Engineer’s Notebook, TTL was always a problem. That narrow 4.75 V to 5.25 V spec for Vcc was hard to hit, thanks to being too poor to buy or build a dedicated 5 V power supply. Yes, I could have wired up four 1.5 V dry cells and used a series diode to drop it down into range, but that was awkward and went through batteries pretty fast once you got past more than a few chips.

As a hobbyist, the five volt TTL standard always seemed a little capricious, but I strongly suspected there had to be a solid reason behind it. To get some insights into the engineering rationale, I did what anyone living in the future would do: I asked ChatGPT. My question was simple: “How did five volts become the standard voltage for TTL logic chips?” And while overall the answers were plausible, like every other time I use the chatbot, they left me wanting more.

Circular Logic

TTL, 5 volts and going strong since 1976 (at least). Source: Audrius Meskauskas, CC BY-SA 3.0.
The least satisfying of ChatGPT’s answers all had a tinge of circular reasoning to them: “IBM and other big computer makers adopted 5 V logic in their designs,” and thanks to their market power, everyone else fell in line with the five volt standard. ChatGPT also blamed “The Cascade Effect” of Texas Instruments’ standardization of five volts for their TTL chips in 1964, which “set the tone for decades” and forced designers to expect chips and power supplies to provide five volt rails. ChatGPT also cited “Compatibility with Existing Power Supplies” as a driver, and that regulated five volt supplies were common in computers and military electronics in the 1960s. It also cited the development of the 7805 linear regulator in the late 1960s as a driver.

All of this seems like nonsense, the equivalent of saying, “Five volts became the standard because the standard was five volts.” What I was after was an engineering reason for five volts, and luckily, an intriguing clue was buried in ChatGPT’s responses along with the drivel: the characteristics of BJT transistors, and the tradeoffs between power dissipation and speed.

The TTL family has been around for a surprisingly long time. Invented in 1961, TTL integrated circuits have been used commercially since 1963, with the popular 7400-series of logic chips being introduced in 1964. All this development occurred long before MOS technology, with its wider supply range, came into broad commercial use, so TTL — as well as all the precursor logic families, like diode-transistor logic (DTL) and resistor-transistor logic (RTL) — used BJTs in all their circuits. Logic circuits need to distinguish between a logical 1 and a logical 0, and using BJTs with a typical base-emitter voltage drop of 0.7 V or so meant that the supply voltage couldn’t be too low, with a five volt supply giving enough space between the high and low levels without being too susceptible to noise.
The 1961 patent for TTL never mentions 5 volts; it only specifies a “B+”, which seems like a term held over from the vacuum tube days. Source: U.S. Patent 3283170A.
But, being able to tell your 1s and 0s apart really only sets a minimum for TTL’s supply rail. Why couldn’t it have been higher? It could have, and a higher Vcc, like the 10 V to 15 V used in emitter-coupled logic (ECL), might have improved the margins between logic levels and improved noise immunity. But higher voltage means more power, and power means heat, and heat is generally frowned upon in designs. So five volts must have seemed like a good compromise — enough wiggle room between logic levels, good noise immunity, but not too much power wasted.

I thought perhaps the original patent for TTL would shed some light on the rationale for five volts, but like most inventors, James Buie left things as broad and non-specific as possible in the patent. He refers only to “B+” and “B-” in the schematics and narrative, although he does calculate that the minimum for B+ would be 2.2 V. Later on, he states that “the absolute value of the supply voltage need be greater than the turn-on voltage of the coupling transistor and that of the output transistor,” and in the specific claims section, he refers to “a source of EMF” without specifying a magnitude. As far as I can see, nowhere in the patent does the five volt spec crop up.

Your Turn

The Fender “Champ” guitar amp had a rectifier tube with a 5-volt filament. Perhaps TTL’s Vcc comes from that? Source: SchematicHeaven.net.
If I were to hazard a guess, the five volt spec might be a bit of a leftover from the tube era. A very common value for the heater circuit in vacuum tubes was 6.3 V, itself a somewhat odd figure that probably stems from the days when automobiles used 6 V electrical systems, which were really 6.3 V thanks to using three series-connected lead-acid cells with a nominal cell voltage of 2.1 V each.

Perhaps the early TTL pioneers looked at the supply rail as a bit like the heater circuit, but nudged it down to 5 V when 6.3 V proved a little too hot. There were also some popular tubes with heaters rated at five volts, such as the rectifier tubes found in guitar amplifiers like the classic Fender “Champ” and others. The cathodes on these tubes were often directly connected to a dedicated 5 V winding on the power transformer; granted, that was 5 V AC, but perhaps it served as a design cue once TTL came around.

This is, of course, all conjecture. I have no idea what was on the minds of TTL’s designers; I’m just throwing out a couple of ideas to stir discussion. But what about you? Where do you think the five volt TTL standard came from? Was it arrived at through a stringent engineering process designed to optimize performance? Or was it a leftover from an earlier era that just happened to be a good compromise? Was James Buie an electric guitarist with a thing for Fender? Or was it something else entirely? We’d love to hear your opinions, especially if you’ve got any inside information. Sound off in the comments section below.

hackaday.com/2025/10/08/ask-ha…

Taking on a refrigerator-sized minicomputer is not for the faint-hearted, but [Usagi Electric] has done it with a DEC PDP-11/44. He’s not doing it in half measures either, for his machine is tricked out with an impressive array of upgrades. Among them however is no storage, and with two co-processors there’s a meager 3U of rack space left. The plan is to fit a period 8″ hard drive in the space alongside a TU50 tape dive, and it’s this final component that’s the subject of his latest video.

DEC never did anything by halves, and a DECTape II cartridge is more than a simple container for tape reels. Instead it has a capstan of its own that engages with one in the drive, and an internal drive belt that moves the reels. All the rubber parts in both tapes and drive are thoroughly perished, and it’s impressive that he manages to find inexpensive modern polymer alternatives. The original drive is probably intended for a VAX system, thus it has the interesting feature of a second drive mechanism out of sight to hold a tape containing microcode.

Having reconditioned the drive, it goes in behind a custom front panel, and though there’s no useful data to test it with on the tapes he has, it appears all working. You can see it all in the video below the break, and if you’re interested further we’ve covered this machine in the past.

youtube.com/embed/KmZ9xGP6O4s?…

hackaday.com/2025/10/08/a-mini…

Glasses are perhaps the most non-invasive method of vision correction, followed by contact lenses. Each have their drawbacks though, and some seek more permanent solutions in the form of laser eye surgeries like LASIK, aiming to reshape their corneas for better visual clarity. However, these methods often involve cutting into the eye itself, and it hardly gets any more invasive than that.

A new surgical method could have benefits in this regard, allowing correction in a single procedure that requires no lasers and no surgical cutting of the eye itself. The idea is to use electricity to help reshape the eye back towards greater optical performance.

The Eyes Have It

Thus far, the research has worked with individual eyeballs. Great amounts of work remain before this is a viable treatment for eyes in living subjects. Credit: research paper
Existing corrective eye surgeries most often aim to fix problems like long-sightedness, short-sightedness, and astigmatism. These issues are generally caused by the shape of the cornea, which works with the lens in the eye to focus light on to the light-sensitive cells in the retina. If the cornea is misshapen, it can be difficult for the eye to focus at close or long ranges, or it can cause visual artifacts in the field of view, depending on the precise nature of the geometry. Technologies like LASIK reshape the cornea for better performance using powerful lasers, but also involve cutting into the cornea. The procedure is thus highly invasive and has a certain recovery time, safety precautions that must be taken afterwards, and some potential side effects. A method for reshaping the eye without cutting into it would thus be ideal to avoid these problems.

Enter the technology of Electromechanical Reshaping (EMR). As per a new paper, researchers at the University of California, Irvine, came across the idea by accident, having been looking into the moldable nature of living tissues. As it turns out, collagen-based tissues like the cornea hold their structure thanks to the attractions between oppositely-charged subcomponents. These structures can be altered with the right techniques. For example, since these tissues are laden with water, applying electricity can change the pH through electrolyzation, altering the attraction between components of the tissue and making them pliable and reformable. Once the electric potential is taken away, the tissues can be restored to their original pH balance, and the structure will hold firm in its new form.
The untreated lens is visible in section A, and the new shape of the modified lens can be seen in section B. Graphs C and D show the change in radius and refractive power of the lens. Credit: research paper
Researchers first tested this technique out on other tissues before looking to the eye. The team were able to use EMR to reshape ears from rabbits, while also being able to make physical changes to scar tissue in pigs. These efforts proved the basic mechanism worked, and that it could have applicability to the cornea itself.

To actually effectively reshape the cornea using this technique, a sort of mold was required. To that end, researchers created a “contact lens” type device out of platinum, which was formed in the desired final shape of the cornea. A rabbit eyeball was used in testing, doused in a saline solution to mimic the eye’s natural environment. The platinum device was pushed on to the eye, and used as an electrode to apply a small electrical potential across the eyeball. This was controlled carefully to precisely change the pH to the region where the eye became remoldable. After a minute, the cornea of the rabbit eyeball had conformed to the shape of the platinum lens. With the electrical potential removed, the pH of the eyeball was returned to normal and the cornea retained the new shape. The technique was trialled on twelve eyeballs, with ten of those treated for a shortsightedness condition, also known as myopia. In the case of the myopic eyeballs, all ten were successfully corrected the cornea, creating improved focusing power that would correspond to better vision in a living patient’s eye.

While the technique is promising, great development will be required before this is a viable method for vision correction in human patients. Researchers will need to figure out how to properly apply the techniques to eyeballs that are still in living patients, with much work to be done with animal studies prior to any attempts to translate the technique to humans. However, it could be that a decade or two in the future, glasses and LASIK will be increasingly less popular compared to a quick zap from the electrochemical eye remoulder. Time will tell.

hackaday.com/2025/10/08/reshap…

L’americano Nick Ray, affetto da sclerosi laterale amiotrofica, ha raccontato di aver trascorso tre giorni a controllare il suo braccio robotico assistito (ARA) utilizzando l’interfaccia neurale Neuralink. L’ha descritta come una delle esperienze più incredibili della sua vita.

Ray ha osservato che, per la prima volta dopo molti anni, era in grado di indossare un cappello, riscaldare il cibo, mangiare, aprire il frigorifero e richiudere i coperchi dei barattoli.

Ha anche provato a guidare una sedia a rotelle e ha stabilito dei record personali: ha spostato 39 cilindri in cinque minuti ed eseguito cinque movimenti precisi in un test di destrezza. Ha promesso di pubblicare un video dei suoi successi .

Ha ringraziato il team di Neuralink e il Fondo Buoniconti per l’opportunità di partecipare al progetto e ha sottolineato che la tecnologia sta ripristinando le opportunità perdute. Ray sta anche lavorando al suo progetto crittografico, che, a suo dire, è diventato un modo per esplorare qualcosa di completamente nuovo e dimostra come le interfacce di comunicazione interconnesse (BCI) possano aiutare non solo con l’attività fisica, ma anche con quella digitale.

Neuralink descrive l’obiettivo dell’esperimento come il ripristino delle capacità motorie di base e dell’indipendenza nelle persone con gravi disturbi del movimento. L’azienda continua a testare l’interfaccia cervello-computer e pubblica i dettagli della sperimentazione sul suo sito web ufficiale.

In precedenza, nel settembre 2024, Neuralink aveva ricevuto l’approvazione della FDA per testare un impianto per il ripristino della vista. Nel novembre dello stesso anno, l’azienda aveva presentato una protesi controllata mentalmente , che consentiva ai pazienti di afferrare e muovere oggetti.

Nell’aprile 2025, Neuralink ha dimostrato come l’impianto potesse ripristinare la parola : il sistema riconosceva le intenzioni e sintetizzava le voci basandosi sui segnali neurali. Uno dei primi passi ha riguardato esperimenti con il controllo del cursore e giochi controllati dalla mente, in cui il paziente controllava un computer senza muoversi.

E nel settembre 2025, l’azienda ha svelato i piani per tradurre i pensieri in testo, consentendo alle persone di comunicare direttamente e controllare i dispositivi attraverso un’interfaccia neurale.

L'articolo Uomo con sclerosi laterale amiotrofica controlla braccio robotico con Neuralink proviene da il blog della sicurezza informatica.

Steve and James discuss The Black Response’s excellent Abolition and Alternatives Conference this weekend and Trump’s TikTok deal and what it could mean. We also discussed ICE and other TLAs attacking an apartment building in Chicago in the middle of the night where they seized and abused the people who lived in it. Finally, we followed up on HorizonMass/BINJ’s reporting on the Boston Police Department’s use of drones at two public events. youtube.com/embed/I-w5-TZR6v4?… Join us at the Boston Anarchist Bookfair Nov. 1-2. Sign up to our newsletter to get notified of new events or volunteer. Join us on:

• Mastodon;
• Facebook;
• Blue Sky;
• Twitter.

Check out:

• Our Administrative Coup Memory Bank;
• Our Things to Do when Fascists are Taking Over.

Some links we mentioned:

• The GOP’s Government Shutdown;
• Abolition and Alternatives Conference (AAC) Starts Today;
• TikTok’s algorithm will be overseen by Oracle in the US after the sale is completed;
• TikTok’s U.S. operations may be bought by Oracle, Andreessen Horowitz, Silver Lake and others;
• Trump Makes It Very Clear They’re Going To Turn TikTok Into A Right Wing Propaganda Machine;
• Why Do We Assume TrumpTok Will Succeed?
• Chicago And The End Of American Liberty;
• Boston Police Deployed 71 Drone Flights Over Caribbean Carnival;
• Did The BPD Fly A Surveillance Drone Over The Dominican Parade? They Won’t Tell Us.

Image Credit: Fair use of TikTok‘s logo for commentary on news about the company. We reserve no rights on the image we creat

uspirates.org/mass-pirate-news…

A partire dal 7 ottobre 2025, si è verificata un’intensificazione su larga scala di attacchi specifici contro i portali di accesso GlobalProtect di Palo Alto Networks, PAN-OS. Oltre 2.200 indirizzi IP unici sono stati coinvolti in attività di ricognizione.

Un notevole incremento è stato rilevato rispetto ai 1.300 indirizzi IP iniziali rilevati solo pochi giorni prima. Secondo il monitoraggio di GreyNoise Intelligence, questo rappresenta l’attività di scansione più intensa degli ultimi 90 giorni.

Il 3 ottobre 2025, un’impennata significativa dell’attività di scansione, pari al 500%, ha contrassegnato l’inizio della campagna di ricognizione. In quel giorno, sono stati rilevati circa 1.300 indirizzi IP unici che stavano esplorando i portali di accesso di Palo Alto. Rispetto ai tre mesi precedenti, questo picco iniziale di attività ha costituito il più alto livello di scansioni registrate.

Nei 90 giorni che hanno preceduto tale evento, i volumi giornalieri di scansioni non avevano quasi mai raggiunto la soglia dei 200 IP.

L’analisi condotta da GreyNoise ha messo in luce che una quota preponderante degli indirizzi IP nocivi, ben il 91%, risulta essere ubicata negli Stati Uniti. Si rilevano inoltre altri nuclei concentrati di tali indirizzi rispettivamente nel Regno Unito, nei Paesi Bassi, in Canada e nella Russia.

Un sostanziale investimento infrastrutturale per tale operazione è evidenziato dal fatto che gli specialisti della sicurezza hanno individuato intorno al 12% delle subnet ASN11878 complessivamente dedicate alla scansione dei gate di accesso Palo. E’ probabile che gli artefici della minaccia stiano esaminando in modo sistematico ampi database di credenziali, visti i pattern di autenticazione falliti che fanno supporre l’utilizzo di operazioni automatizzate brute-force nei confronti dei portali GlobalProtect SSL VPN.

GreyNoise ha reso pubblico un dataset esaustivo che include nomi utente e password univoci ricavati dai tentativi di login a Palo monitorati, in modo da permettere ai team per la sicurezza di stimare l’eventuale esposizione delle credenziali. Dall’analisi tecnica emerge che il 93% degli indirizzi IP coinvolti è stato etichettato come sospetto, mentre un 7% è stato giudicato dannoso.

L’esame delle attività di scansione rivela la presenza di diversi pattern di aggregazione a livello regionale contraddistinti da impronte TCP uniche, il che fa supporre l’esistenza di vari gruppi di minacce organizzate che agiscono in concomitanza. Gli studiosi nel campo della sicurezza hanno rilevato possibili legami tra la serie di scansioni registrata a Palo Alto e le operazioni di esplorazione condotte simultaneamente contro dispositivi Cisco ASA.

Entrambe le campagne di attacco condividono impronte TCP dominanti legate all’infrastruttura nei Paesi Bassi, insieme a comportamenti di clustering regionale e caratteristiche degli strumenti simili. L’attacco multitecnologico suggerisce una campagna di ricognizione più ampia contro le soluzioni di accesso remoto aziendale.

L'articolo Ondata di attacchi contro Palo Alto Networks: oltre 2.200 IP coinvolti nella nuova campagna proviene da il blog della sicurezza informatica.