Other fun book facts: by looking at the length of the number that is the second to last digit in the ISBN, you can tell how many large an ISBN block the publisher bought, which often relates to the size of the publisher. If it's only two digits, they only bought a block of 100 ISBN's, so they're probably a very small publisher. https://en.wikipedia.org/wiki/International_Standard_Book_Nu...
Printer's key
11–17 of 17 posts
Re: Printer's key
#12Nice. Reminds me of the explanation why the code for DEL (delete) in ASCII is 127 (1111111) -- back in the days of punchcards, when a punched hole meant "one" and no hole meant "zero", you could convert any other code into 1111111 by overstriking it (similar to how in the days of typewriters you could overstrike any other letter with X to cross it out).
Re: Printer's key
#13Nice. Reminds me of the explanation why the code for DEL (delete) in ASCII is 127 (1111111) -- back in the days of punchcards, when a punched hole meant "one" and no hole meant "zero", you could convert any other code into 1111111 by overstriking it (similar to how in the days of typewriters you could overstrike any other letter with X to cross it out).
Close, but that only worked for punched paper tape (which had 7 positions for hole / not-hole per row, with a direct mapping to ASCII). Punch cards used Hollerith code, with 12 positions per column, with a peculiar mapping to EBCDIC, where there would be only one hole in rows 1 to 8, which more or less gave the bottom 3 bits of the character, and a combination of holes in the other 4 rows, giving the other 4 bits.
Re: Printer's key
#14If you find this interesting, you'll love http://www.linotypefilm.com/. It was on Amazon Prime Video about a year ago.
Re: Printer's key
#15Nice. Reminds me of the explanation why the code for DEL (delete) in ASCII is 127 (1111111) -- back in the days of punchcards, when a punched hole meant "one" and no hole meant "zero", you could convert any other code into 1111111 by overstriking it (similar to how in the days of typewriters you could overstrike any other letter with X to cross it out).
Close, but that only worked for punched paper tape (which had 7 positions for hole / not-hole per row, with a direct mapping to ASCII). Punch cards used Hollerith code, with 12 positions per column, with a peculiar mapping to EBCDIC, where there would be only one hole in rows 1 to 8, which more or less gave the bottom 3 bits of the character, and a combination of holes in the other 4 rows, giving the other 4 bits.
Thank you!
Re: Printer's key
#16In summary, what book printers used to do is have a line of numbers on the title page of the book, which they would erase one at a time with each printing run. The reason why is that they would be reusing the original plates in the printing press, and it was easy to erase a number (by destructively removing it from the plate) as opposed to recreating a whole new plate for the title page. Flash memory works in a simil…
Does that mean that it's better to securely erase flash disks with FF's rather than 00's?
Re: Printer's key
#17In summary, what book printers used to do is have a line of numbers on the title page of the book, which they would erase one at a time with each printing run. The reason why is that they would be reusing the original plates in the printing press, and it was easy to erase a number (by destructively removing it from the plate) as opposed to recreating a whole new plate for the title page. Flash memory works in a simil…
Does that mean that it's better to securely erase flash disks with FF's rather than 00's?
There is no difference from security point of view. To erase SSD you just TRIM[0] the whole device and wait some time while it erases underlying flash.