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Annotation of coherent/a/usr/man/COHERENT/lp, revision 1.1.1.1

1.1       root        1: 
                      2: 
                      3: lp                        Device Driver                        lp
                      4: 
                      5: 
                      6: 
                      7: 
                      8: Line printer driver
                      9: 
                     10: 
                     11: Files /dev/lp*  access the line-printer's device  drivers for IBM
                     12: AT COHERENT.  The drivers are assigned major device number 3.
                     13: 
                     14: The COHERENT  system supports three printers,  in both cooked and
                     15: raw modes.   The following gives  the device name,  minor device,
                     16: and I/O port:
                     17: 
                     18: 
                     19:      /ddeevv/llpptt11 0  0x3BC  (/etc/mknod /dev/lpt1  c 3   0)
                     20:      /ddeevv/llpptt22 1  0x378  (/etc/mknod /dev/lpt2  c 3   1)
                     21:      /ddeevv/llpptt33 2  0x278  (/etc/mknod /dev/lpt3  c 3   2)
                     22:      /ddeevv/rrllpptt11128  0x3BC  (/etc/mknod /dev/rlpt1 c 3 128)
                     23:      /ddeevv/rrllpptt22129  0x378  (/etc/mknod /dev/rlpt2 c 3 129)
                     24:      /ddeevv/rrllpptt33130  0x278  (/etc/mknod /dev/rlpt3 c 3 130)
                     25: 
                     26: 
                     27: ``Cooked'' processing processes  the special characters BS (back-
                     28: space), HT (horizontal tab),  LF (line feed), FF (form feed), and
                     29: CR (carriage return)  appropriately; raw processing simply passes
                     30: them on to the printer.
                     31: 
                     32: The driver uses  a hybrid busy-wait/timeout discipline to support
                     33: printers efficiently  that have varying buffer  sizes in a multi-
                     34: tasking environment.
                     35: 
                     36: The kernel variable LPWAIT  is the time during that the processor
                     37: waits  for the  printer  to accept  the next  character.  If  the
                     38: printer  is not  ready within  the LPWAIT  time period,  the then
                     39: processor resumes  normal processing for the  number of ticks set
                     40: by  LPTIME Thus,  setting LPWAIT  to a  very large  number (e.g.,
                     41: 30,000) and LPTIME to a  very small number (e.g., one) results in
                     42: a fast printer,  but slow processing on other tasks.  Conversely,
                     43: setting LPWAIT to a small number (e.g., 50) and LPTIME to a large
                     44: number (e.g.,  five) result in efficient  multi-tasking, but also
                     45: results in  a slow printer  unless the printer  itself contains a
                     46: buffer (as  is presently normal with all  except the least expen-
                     47: sive printers).   By default, LPWAIT is set to  100 and LPTIME to
                     48: four.  We recommend  that you set LPWAIT to no  less than 50, and
                     49: LPTIME to no less than one.
                     50: 
                     51: ***** Files *****
                     52: 
                     53: /ddeevv/llpp* -- ``Cooked'' printer interfaces
                     54: /ddeevv/rrllpp* -- Raw printer interfaces
                     55: 
                     56: ***** See Also *****
                     57: 
                     58: ascii, device drivers, epson, lpr
                     59: 
                     60: 
                     61: 
                     62: 
                     63: 
                     64: COHERENT Lexicon                                           Page 1
                     65: 
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