iglesias@ICS.UCI.EDU (Mike Iglesias) (08/06/86)
We're looking at getting an Imagen 8/300 (now known as the Imagestation XP 2308). It will be used on a VMS system for TeX and graphics output from several packages that can generate Tek 4014 output. People want to be able to do 'full page graphics'. The Imagen rep says we need at least 2mb of memory to do that. Does anybody have any experience doing graphics on an Imagen? Is 2mb enough? What does more memory buy us? Mike Iglesias University of California, Irvine
geof@imagen.UUCP (Geof Cooper) (08/06/86)
> We're looking at getting an Imagen 8/300 (now known as the Imagestation > XP 2308). It will be used on a VMS system for TeX and graphics output > from several packages that can generate Tek 4014 output. People want to > be able to do 'full page graphics'. The Imagen rep says we need at least > 2mb of memory to do that. Does anybody have any experience doing > graphics on an Imagen? Is 2mb enough? What does more memory buy us? IMAGEN printers translate input into an intermediate format. This format is then rasterized "on the fly" as the printer is printing. The presence of an intermediate format allows the printers to perform such feats as pagecollation, complex jam recovery, and duplexing without the need to store full page rasters. The memory utilization of the printer is essentially fixed except for this storage of page objects. To be able to print a page, you have to be able to store the page's intermediate form entirely in memory before starting to print. Extra memory in the printer allows one to print more complex pages, since larger page objects can be stored. It also allows one to collate larger documents. Typically, page objects are very small (<=20KB). Since the complexity of each page is unbounded, it is possible to define a page whose intermediate form is dramatically larger than typical, sometimes even larger than the full page raster into which the intermediate form is translated on printing. This happens in some CAD or mapping applications, where thousands of vectors are drawn on each page. To avoid this situation, the printer can be instructed to operate in "prerasterization mode," through use of a special document control prefix. In prerasterization mode, rasterization is performed synchronously with compilation, and the page object looks as if you had sent a series of impress bitmap commands to the printer. The prerasterized page object's size is roughly based on the percentage of black on the page, and can be as great as a full page bitmap (1.003 MB for an 8/300). [Prerasterization can also be used to print documents whose overall complexity is small, but is concentrated in one portion of the page.] Another case where page objects can get large is when printing bitmaps that cover a large portion of the page. If the bitmaps do no overlap, prerasterization is unecessary, and the maximum size of the page object is the same maximum as for prerasterization (1.003 MB). If the bitmaps do overlap, prerasterization can be used to fold all the bitmaps into one in the printer. A printer with enough storage for a full page bitmap (as well as code, data, comm buffers, etc.) can print any input, regardless of complexity, by resorting to prerasterization mode. This translates to a requirement for 2MB of memory. More memory would allow collation of larger documents, but would not provide enhanced graphics capabilities. A printer which is fully loaded with memory can probably page reverse more than 100 pages of text and scattered "business graphics." Hope this answers your question. - Geof Cooper IMAGEN