Buffer Overflow
This series explores the phenomenon of buffer overflow. To control
vintage plotters, we use the classic rs232 serial interface, sending
HPGL commands to the device. These plotters, like the HP 7475A featured
in this series, have a small memory capacity of e.g. 1024 bytes. It's
the user's job to prevent the machine's internal buffer from being
overloaded by sending too much data at once. This can be managed through
either hardware or software handshakes.
In the creation of these pieces, we intentionally skip the handshake
process. This ensures that buffer overflows will occur, but it's
unpredictable exactly when they will happen, making it impossible to
recreate the same overflow twice.
The consequence of a buffer overflow is that the plotter's interpreter
misses some commands, which might lead to, for example, drawing lines
without having selected a pen. Other times, unexpected diagonal lines
appear if the plotter's firmware goes into an error state.
About HP-GL (from the HP7475A manual)
HP-GL (Hewlett-Packard Graphics Language) is the graphics programming
language that is actually sent to and understood by the plotter. HP-GL
instructions consist of two-letter mnemonics that are usually followed
by numeric parameters. With the exception of certain escape sequence
instructions which are used for control of interface functions in an
RS-232-C environment, all data received by the plotter is interpreted as
HP-GL instructions. You can include HP-GL instructions directly in the
computer language output statements, or you can use AGL statements which
the computer encodes and sends to the plotter as HP-GL instructions.
An excerpt from the HP 7475A's manual about the handhshaking options
These are some test-files that were the base for the drawings of this series. These are calibration tests to get an idea of the ink-flow at certain speeds of moving the pen over paper.
big shout out to @ithinkido for the test-files and help setting up all these plotters
🔴
Work in progress, plotted on a vintage HP 7475A plotter using rotring archival ink
buffer overflow 🔴
black archival ink
297x420mm/11.69x16.53in (a3)
hicetnunc/35298
buffer overflow
black archival ink
297x420mm/11.69x16.53in (a3)
buffer overflow 🔴
original 80's felt tip pens on paper
297x420mm/11.69x16.53in (a3)
buffer overflow
black archival ink
297x420mm/11.69x16.53in (a3)
buffer overflow
original 80's felt tip pens on paper
297x420mm/11.69x16.53in (a3)
buffer overflow 🔴
original 80's felt tip pens on paper
297x420mm/11.69x16.53in (a3)
hicetnunc/1083
buffer overflow
original 80's felt tip pens on paper
297x420mm/11.69x16.53in (a3)
buffer overflow 🔴
original 80's felt tip pens on paper
297x420mm/11.69x16.53in (a3)
hicetnunc/577554