ajp11's comments

ajp11 | 1 year ago | on: Ask HN: Where to sell vintage computers?

I have a Sun Ultra 30 with CRT monitor, mouse and keyboard in south London, UK that I have been trying to give away for free for a while.

This thread may push me to try again.

ajp11 | 2 years ago | on: Ask HN: What do you do with your RTL SDR?

I looked at several radio microphones, which were used in different bars in a building with local sound systems. Some of the microphones had been mixed up between rooms and some were entirely lost.

There is some software called Spektrum which I found handy for looking at the full range up to 1GHz to see roughly where the microphones where transmitting then zooming in.

Writing down a list of the microphone frequencies and the frequencies on the labels on the receivers let me figure out what was going on with less running around.

ajp11 | 3 years ago | on: Where do stolen bikes go?

In the summer of 1997, I was sitting in the center of Amsterdam enjoying the sunshine on a warm bright afternoon. I saw a man wearing a wooly jumper walk up to a bike rack, pull out a pair of bolt cutters, snip a lock and ride away.

When I passed through Amsterdam for the first time I recall looking at the many bikes at the bike racks and thinking how old fashioned they all looked, I think it is still the same now.

ajp11 | 3 years ago | on: Ask HN: What do I spend my training allowance on?

How about a first aid course? It looks good on a C.V.

"Boss, this course will tell me what to do when an unfit, overweight, 55 year old middle manger appears to be having a heart attack in the office."

Bonus if you can get out of the office for a day to do it.

If you can spend a years budget in one go you could do a one day course to learn to operate cherry pickers and scissor lifts, although that usually involves travelling to a distant industrial estate early in the morning.

It sounds like you are a programmer. The BCS offer a few certifications where you can just read the material and take and exam to get a cert that might look good on your CV.

"Wellbeing"?, Hey boss, can I buy a split keyboard and a vertical mouse to avoid RSI and carpal tunnel syndrome?

"Learning", Hey boss, this trade show that is relevant to our industry has some educational seminars, can I use my budget for train tickets and lunch and be out of the office for a day?

ajp11 | 3 years ago | on: Large scale Internet SSH brute force attacks seem to have stopped here

Fail2ban blocked 1087 ip addresses in the last week, which seems normal.

I reset it and it has blocked eleven ip addresses in the last hour, mainly China and Digital Ocean as usual.

Just to see what happens, I'v tried sending abuse reports about ssh brute force, vnc brute force and phishing sites, by the standard method of doing a whois lookup on the ip for the abuse email address.

Some server and web hosting companies take the inconvenient approach of having an email auto-reply that says "we ignore all emailed abuse reports, you must use this web form", sometimes requiring a captcha.

When I reported a load of boxes attempting brute force logins, most complaints disappeared into the void.

I got a few responses from virtual server providers saying "no response from the customer after two weeks so we shut down the box" and one CC:ed email that appeared to be from an end user saying "we have reinstalled the box and changed the password."

ajp11 | 3 years ago | on: Teardown of a quartz crystal oscillator and the tiny IC inside

For that reason: cheap available quartz crystals, since the 1970s, the shortwave radio frequency 3.579Mhz has been a spot on the dial where radio hams use low power home made morse code transmitters. At night, a range of a couple of hundred files is usually possible.

ajp11 | 3 years ago | on: Original Pong did not have any code or even a microprocessor

In the year 1974, Practical Wireless, a UK magazine, published a design for a pong game that connects to a television, called PW Tele Tennis.

It uses sixty four NAND gates, twelve NE555 timers, two dozen diodes and some analog parts.

It's about the most basic version of the game. They later published a sound effects board and an on-screen scoring board that uses a couple of dozen more chips.

http://searle.x10host.com/TeleTennis/PWTennis.html

ajp11 | 4 years ago | on: Backer: Storing data on VHS tapes (2003)

I think I still have an ISA bus Backer card in a box somewhere.

I got it second-hand for not much money and was pleased to have it. At the time, it was the only practical way for me to back up my 500MB harddrive.

My vague recollection is that the software that was supplied with it, for windows 3.11, could store about 500MB on a three hour VHS tape.

I tried various settings in the software and reading a tape holding files of mostly under 1MB in size always gave a checksum error on two or three files.

A different VCR might have worked better.

I would let a backup run for three hours, wait another three hours to play back the tape then copy the few files that could not be read to a floppy disk and keep it with the video cassette.

ajp11 | 4 years ago | on: Who is squatting IPv4 addresses?

A couple of years ago Amazon bought four million ip addresses for $108 million dollars. 44.192.0.0/10

AMPRnet sold them a quarter of the ip addresses that were allocated for amateur radio. They got a /8 back in the 1980s. A small number of addresses were used for ham radio networks but the AMPRnet addresses were generally not routed between the internet and the radio networks.

page 1