Broadcast Engineer at BellMedia, Computer history buff, compulsive deprecated, disparate hardware hoarder, R/C, robots, arduino, RF, and everything in between.
5116 stories
·
5 followers

Calculate pi to an arbitrary number of decimal places

1 Share
$ bc -l <<< "scale=1000; 4*a(1)"

commandlinefu.com

Diff your entire server config at ScriptRock.com

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete

Monitor ETA using pv command

1 Share
$ mysqldump --login-path=mypath sbtest sbtest4 | pv --progress --size 200m -t -e -r -a > dump.sql
You can get an approximate idea of how long your data export might take.

commandlinefu.com

Diff your entire server config at ScriptRock.com

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete

Get Your Weather Images Straight from the Satellite

2 Shares

[Josh] has a series called Ham Radio Crash Course and a recent installment covers how you can grab satellite images directly from weather satellites. This used to be more of a production than it is now thanks to software defined radio (SDR). Josh also has another project using a 3D printer to make an antenna suitable for the job. You can see the video below.

The software is the venerable WXtoImg program. This is abandonware, but the community has kept the software available. The program works on Linux, Windows, and Mac. The satellites in question operate around 137 MHz, but that’s easily in the range of even the cheap SDR dongles. [Josh] shows how to use a virtual audio cable on Windows to connect the output of the radio to the input of the WXtoImg program. Under Linux, you can do this with Pulse or Jack very easily without any extra hardware.

There’s some setup and calibration necessary for the software. You’ll also need the current orbital data and the program will tell you when you can find the next satellite passing overhead. Generally speaking you’ll want your antenna outside, which [Josh] solved by taking everything outdoors and having some lunch during the pass. It also takes some time to post-process the data into images and audio.

We know this isn’t new. But we did like [Josh’s] clear and up-to-date guide. We remember watching NOAA 15 as it started to lose its electronic mind.

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete

Dissecting China-Sourced Vintage HP 1970s ICs: Genuine Or Not?

1 Share

While repairing a real-time clock module for a 1970s HP computer that had been damaged by its leaky internal battery, [CuriousMarc] began to suspect that maybe the replacement clock chips which he had sourced from a seller in China were the reason why the module still wasn’t working after the repairs. This led him down the only obvious path: to decap and inspect both the failed original Ti chip and the replacement chip.

The IC in question is the Texas Instruments AC5948N (along with the AC5954N on other boards), which originally saw use in LED watches in the 1970s. HP used this IC in its RTC module, despite it never having been sold publicly. This makes it even more remarkable that a Chinese seller had the parts in stock. As some comments on the YouTube video mention, back then there wasn’t as much secrecy around designs, and it’s possible someone walked out of the factory with one of the masks for this chip.

Whether true or not, as the video (also included after the break) shows, both the original 1970s chip and the China-sourced one look identical. Are they original stock, or later produced from masks that made their way to Asia? We’ll probably never know for sure, but it does provide an exciting opportunity for folk who try to repair vintage equipment.

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete

Side-Channel Attacks Hack Chat with Samy Kamkar

1 Share

Join us on Wednesday, March 25 at noon Pacific for the Side-Channel Attacks Hack Chat with Samy Kamkar!

In the world of computer security, the good news is that a lot of vendors are finally taking security seriously now, with the result that direct attacks are harder to pull off. The bad news is that in a lot of cases, they’re still leaving the side-door wide open. Side-channel attacks come in all sorts of flavors, but they all have something in common: they leak information about the state of a system through an unexpected vector. From monitoring the sounds that the keyboard makes as you type to watching the minute vibrations of a potato chip bag in response to a nearby conversation, side-channel attacks take advantage of these leaks to exfiltrate information.

Side-channel exploits can be the bread and butter of black hat hackers, but understanding them can be useful to those of us who are more interested in protecting systems, or perhaps to inform our reverse engineering efforts. Samy Kamkar knows quite a bit more than a thing or two about side-channel attacks, so much so that he gave a great talk at the 2019 Hackaday Superconference on just that topic. He’ll be dropping by the Hack Chat to “extend and enhance” that talk, and to answer your questions about side-channel exploits, and discuss the reverse engineering potential they offer. Join us and learn more about this fascinating world, where the complexity of systems leads to unintended consequences that could come back to bite you, or perhaps even help you.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 25 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete

Ken Shirriff Unfolds a Nuclear Missile Guidance Computer with Impressive Memory

1 Share

Longtime followers of [Ken Shirriff’s] work are accustomed to say asking “Where does he get such wonderful toys?”. This time around he’s laid bare the guidance computer from a Titan missile. To be specific, this is the computer that would have been found in the Titan II, an intercontinental ballistic missile that you may remember as a key part of the plot of the classic film WarGames. Yeah, those siloed nukes.

Amazingly these computers were composed of all digital logic, no centralized controller chip in this baby. That explains the need for the seven circuit boards which host a legion of logic chips, all slotting into a backplane.

But it’s not the logic that’s mind-blowing, it’s the memory. Those dark rectangles on almost every board in the image at the top of the article are impressively-dense patches of magnetic core memory. That fanout is one of two core memory modules that are found in this computer. With twelve plates per module (each hosting two bits) plus a parity bit on an additional plate, words were composed of 25-bits and the computer’s two memory modules could store a total of 16k words.

This is 1970’s tech and it’s incredible to think that when connected to the accelerometers and gyros that made up the IMU this could use dead reckoning to travel to the other side of the globe. As always, [Ken] has done an incredible job of walking through all parts of the hardware during his teardown. He even includes the contextual elements of his analysis by sharing details of this moment in history near the end of his article.

If you want to geek out a little bit more about memory storage of yore, you can get a handle on core, drum, delay lines, and more in Al Williams’ primer.

Read the whole story
tekvax
4 days ago
reply
Burlington, Ontario
Share this story
Delete
Next Page of Stories