Re: Old typewriter
"we can afford to XOR something a couple million times if we want to."
This is just the same as XORing once with the appropriate pattern.
1019 publicly visible posts • joined 6 Jun 2015
In high school I used to "burn" holes in aluminum pie plates with mercury. The mercury acts as a catalyst and allows the oxygen in the air to get to the aluminum under the oxide and oxidise it. The result is towers of aluminun oxide and, eventually, creates holes in the pie plate.
At Xerox, around 1980, some secretaries ran Interlisp for their desktop (mail, document creation, printing etc.). They never seemed to have a problem. If there was a power failure, on restarting the machine all of the icons, open documents etc. were right where she left them.
It's too bad we can't do this even with a controlled shutdown nowadays.
I run a website on bluehost and about a year ago I discovered I could use http or https on my pages and subdomains. I also discovered some pages on my website I didn't put there but appeared to be challenge/response pages to get the certificates. I do have a "plus" account though.
Getting a free certificate apparently just requires having the ability to put up a web page to show you own/control the website.
When I was a "cute" young boy I was fascinated by phone companies. I was able to get into a dozen or so just by asking. I saw a long distance cord board, #1 crossbar, #4 crossbar, #5 crossbar, a panel office, a 60,000 subscriber step-by-step system (it was awesome and noisy), some ESS systems etc. It was fun to see the technology advance but I always loved the crossbar systems.
Back in 1966 on the Dartmouth time sharing system there was a top-level file that was all of physical memory. It was protected. Someone thought it would be harmless to grant read access to this (pseudo) file. Someone else then discovered a simple password cracker by trying to open up a file and scanning memory for the file name and looking nearby for the password. Worked like a charm.
When I found out about it I asked, "What were you thinking?"
Don't let random people mess with stuff they don't understand.
My group went through sexual harassment training where I worked. It was junk. I finally pointed out that this training was designed to defend the company against lawsuits. They had no answer for this.
A well-built male window washer claimed sexual harassment against secretaries that whistled at him while he was washing windows. I think he won.
Once, when I was teaching computer science, I told the head of IT that if I needed root I would just ask for it. He said he probably wouldn't give it to me. They had reasonably good security in the computer science department.
Then I was trying to debug a suid root program with dtrace or strace (I forget which one) and told the head of IT I needed root. He thought for awhile and opened up a root shell on my machine. Then I discovered that the shared file server didn't trust root credentials from a remote machine. I couldn't even access my own files from the root shell!
So I transferred the relevant files to /tmp and proceeded to successfully debug the suid root program. Good security.
I don't see any mention of the magnetron which was another British invention. The early RADAR frequency was in the OH (water) band and didn't perform as well as it could have. This is perfect for a microwave oven though. The Germans captured some magnetrons but couldn't get them to work very well because they made them perfectly symmetrical.
England also set up several "fake" radio transmitters outside of London to try to mislead the Germans.
At Xerox, where we had all of the bells and whistles for a "paperless office," everyone printed copies of emails, reports etc. The paperless office generated more paper, even at Xerox, where it should have generated less. Oh well.
All languages have their good and bad points. Generally people favor languages that they are familiar with:
LISP - lexical closures, precise garbage collection, can mimic most other languages
JAVA - type erasure, precise garbage collection
C - "machine language" with better syntax
C++ - C + separation of algorithms and containers through iterators
HASKELL/ML - precise garbage collection, list comprehension
Your Favorite Language - stuff, more stuff
What C++ needs is a precise garbage collector although careful coding using values instead of references can eliminate most memory problems.
YMMV
In 1965 I had a problem and access to a real time DN-30 computer that was running the exec for the Dartmouth time sharing system. So I added some tasks to calculate some results on the DN-30. I was using a good fraction of the computer time and the blinkenlights showed an unusual pattern as a result. I got my answers and turned off the program and then realized I could get the same answers, by hand, with paper and pencil quite quickly.
Since the computer was a real time computer there wasn't any appreciable slowdown.
I remember one of the first black hole collisions resulted in 3 solar masses converted to gravitational waves. If the black holes were spinning before the collision then the resulting black hole should be kicked "sideways" a small fraction of the speed of light. I wonder if this happened in this case.