The Multifloria DMV is unable to generate text equivalents for the
binary input files, due to the incompetence of their COBOL
programmers. However, it is possible to learn something about their
structure by "dumping" them using the
od ("octal dump")
command. Despite its name,
od will dump in many formats,
notably ASCII and hexadecimal.
For example, the command:
od -xc simplesparc.binwill show you the contents of
simplesparc.binin both hexadecimal and character form. It is generally easier to interpret the Sparc version than the Intel one, unless you are already expert at that sort of thing. You may wish to ask for help from the graders or professors in interpreting these dumps.
As an example, here are the first few lines of "
simplesparc.bin" (this command must be executed on Turing to get the
0000000 694d 0012 d687 0000 000f 4765 6f66 6620 i M \0 022 326 207 \0 \0 \0 017 G e o f f 0000020 4b75 656e 6e69 6e67 0001 0107 8269 4e00 K u e n n i n g \0 001 001 007 202 i N \0 0000040 74cb b100 0000 0c4a 6f6e 2053 7472 6175 t 313 261 \0 \0 \0 \f J o n S t r a u 0000060 7373 0002 0e07 9869 4c00 12d6 8700 0000 s s \0 002 016 007 230 i L \0 022 326 207 \0 \0 \0 0000100 1547 656f 6666 204b 7565 6e6e 696e 6727 025 G e o f f K u e n n i n g '
Here, we can see that the first character (the command) is an 'i' (insert new driver). The prefix for the license number is 'M'. The next four bytes are the license number, shown in hexadecimal: 0012d687. You can use a calculator to convert this to its decimal equivalent, 1234567. Then come 4 more bytes giving the length of the name string, again in hex: 0000000f, or 15 characters, and then the driver's name, followed by a null byte (00, or \0 as a character). Then are two single bytes giving the birth month (01) and birth day (01), followed by a pair of bytes that together give the birth year (0782 in hex, or 1922 decimal). That's the end of the first record; the next thing in the input is the 'i' command for the second driver.
Many modern calculators include a feature that will convert
hexadecimal numbers to decimal and vice versa. There are also several
programs available under Unix. Two of them are
Dc is an RPN-style
calculator. To convert hex to decimal, start
dc and then
type "16i" to tell it you're typing hex numbers. Then type the number
you want to convert, using uppercase for the digits A-F, and
follow it with the letter "p". Finally, type "q" to quit. For example:
% dc 16i 12D687 p 1234567 q %
Bc will do the same thing, but it uses a non-RPN input
format. Start up
bc and type
the first line, to tell it you are typing hex numbers. Then whenever
you type something in hexadecimal, it will respond with the decimal
equivalent. Again, you must use uppercase characters for the
© 2001, Geoff Kuenning
This page is maintained by Geoff Kuenning.