The 2250 display for the 1130 was an expensive beast, about $200,000 as I remember. Not many around!
The graphics buffer for the 2250 was allocated in the 1130 memory. IPF used an 8K (word) buffer which took a big bite out of the 32k word memory leaving only 24K for programs and data. We had to use locals / socals ( load on call subroutines ) to make it all fit. Being that we worked for IBM we had access to the source code for the Fortran compiler and the 1130 Disk Monitor System (DMS). So we made many "improvements" to both!
One improvement to the DMS was in the boot code to figure out what I/O devices were attached ( 1132 vs 1403 printer, 2501 vs 1442 card reader ) and reconfigure the system to accomodate the hardware configuration. This was necessary because there was no standard hardware configuration among our users and doing it the standard IBM way by changing cards in the config card deck and running it which was a pain in the neck. Our users usually used whatever 1130 system was available to them at the moment and repeatedly reconfiguring their system disk was a pain in the a**!
One of the changes to the Fortran compiler was to add the Fortran internal buffer as an additional read / write device. That way we could use fortran read write and format statements to convert between character strings and integer and real numbers. We could only write characters to the 2250 display, so this allowed us to write to the 2250 screen with Fortran.
The IBM software support for the 2250 was very poor so we used a internally written Graphic Input Outport Support Program ( GIOSP ) which we also heavily modified for our purposes. One of our improvements was an odometer capability to continuously display the coordinates of the light pen as it moved in chip coordinates. GIOSP was written entirely in 1130 assembler.