P112 question - what can you run that uses 1MB of RAM?

On 11/09/2012 07:50 PM, ben wrote: Actually no. To do that you need to be able to process the data rapidly enough to lay down dots as the drum rotates. The key thing for Laser printing (or any page printer) is the bit image need to exist before the paper moves or at least be preprocessed so that the raster image processor can fill a "band buffer" . The Video dot rate for a DEC LN01 (xerox 12PPM engine) was about 7mhz. The early character only version use a 12mhz 80186 with 8089 to keep up, The system IO to the host was handled by the 8089. Oddly the 8PPM LN03 Ricoh based engine was not much slower on the video clock. In the late 80s there were two lasers often those that were band buffer and generally limited to text and limited graphics and a higher priced version that had enough ram to buffer the page so the image could be composed before the paper was even moved. Actually I use my CP/M-80 system to lay down images on a real Laserjet4L. The price is that I need to run the system for a long time to create bit images to transmit. That takes hours even with ram and bit of buffering to hard disk. Even then the printer is doing much of the heavy lifting. The main issue was never ram but CPU cycles to process that data at acceptable rates for graphic images. It is the same issue as doing video graphics on a CRT or LCD. In that case you need enough ram to buffer the image for refresh and enough cpu to create and transfer images to that ram. So to simply move bytes to a 1MB page buffer it would take a Z80 at 4mhz around 8 seconds with no processing other than simple paging. That's too slow. Allison