# Binary on a diet

How can you make binary data less filling?
Remove the 1s, of course.

 OO O OO      O OO OOOO
OO  OO O      O OOO O
OOOOO       OOO  O O
OOO OO       OO OO  O
OOO OO
OOO OOOO
OOO  O  O     O   O  O
OOOO O OO     O O O OO
OO   O OO
OOOO O OO    OO  OO  O
OO  OO O    OO  OO  O
OOO O O
OOOO OOO     OOO  O O
OO  OO O    OOOOOO  O
OOO  OO       OOO OO
OO  OO O
OO OO  O    OOOO O OO
OOO OOOO       O OOOO


Some who remember the 1960s were more into computers than counterculture. They may remember a time when stored text was less filling than now. One reason for that relative efficiency is given in the two-column mystery sentence above, encoded authentically for those days.

What was that reason?

What is this encoding?

• Looks like a punch card, maybe? Apr 4 '16 at 18:41
• Yah. Punchcard with a parity bit. Not at home tho or I'd go for it. Apr 4 '16 at 19:08

Text was served in 7-bit ASCII bytes.

The encoding is

ASCII on a punch tape with sprocket holes after the 5th bit. The first bit is a parity bit.

Each O in the puzzle is a hole that is interpreted as 1 or # here:

Binary        Dec  ASCII     Binary        Dec  ASCII
(1)1010#100    84    T       (1)0110#111    55    7
(0)1100#101   101    e       (0)0101#101    45    -
(0)1111#000   120    x       (1)1100#010    98    b
(0)1110#100   116    t       (0)1101#001   105    i
(0)1110#100   116    t
(0)1110#111   119    w
(1)1100#001    97    a       (0)1000#001    65    A
(1)1110#011   115    s       (0)1010#011    83    S
(1)1000#011    67    C
(1)1110#011   115    s       (1)1001#001    73    I
(0)1100#101   101    e       (1)1001#001    73    I
(0)1110#010   114    r
(1)1110#110   118    v       (1)1100#010    98    b
(0)1100#101   101    e       (1)1111#001   121    y
(1)1100#100   100    d       (0)1110#100   116    t
(0)1100#101   101    e
(0)1101#001   105    i       (1)1110#011   115    s
(1)1101#110   110    n       (0)0101#110    46    .
(To be complete, each space between words would be "O O O " in the puzzle and "(1)0100#000 32" here.)

See also: Newcastle University – Virtual Museum – 8 Hole Paper Tape

• Cool! I didn't notice the sprocket holes, so I thought it was some 8-bit encoding with a 9th parity bit. Do you know if this tape is punched according to an actual punch card standard? Apr 4 '16 at 22:20
• It is a 8 hole punched TAPE. Punch cards need no sprocket holes. See staff.ncl.ac.uk/roger.broughton/museum/iomedia/pt1.htm Apr 5 '16 at 5:39
• A little formal nitpicking though: space characters should still have sprocket holes. This tape might get stuck like this... Apr 5 '16 at 5:41