sm(4)sm(4)Namesm - Small VAX monochrome video subsystem
Syntax
device sm0 at uba0 csr 0x200f0000 flags 0x0f vector smvint
Description
A Small VAX monochrome video subsystem provides a half-page or full-
page, user-accessible bitmap display for graphics applications. The
device consists of a 128-Kbyte block of dual port RAM, a VSXXX-AA mouse
or VSXXX-AB tablet, and a 19-inch video monitor.
The subsystem device driver supports a hybrid terminal with three minor
devices. The first minor device emulates a glass tty with a screen
that appears as a 120-column by 80-row page that scrolls from the bot‐
tom. This device is capable of being configured as the system console.
The second minor device is reserved for the mouse. This device is a
source of mouse state changes. (A state change is defined as an X/Y
axis mouse movement or button change.) When opened, the driver couples
movements of the mouse with the cursor. Mouse position changes are
filtered and translated into cursor position changes in an exponential
manner. Rapid movements result in large cursor position changes. All
cursor positions are range checked to ensure that the cursor remains on
the display.
The third minor device provides an access path for console output that
does not disturb the graphics display. The caller can open the device
When this device is open, the Small VAX monochrome driver redirects
console device output to the input buffer of this device. This mecha‐
nism disables console output on the Small VAX monochrome screen and
saves the output for later display. This preserves the graphic display
integrity.
Input and output on the first and third minor devices are processed by
the standard line disciplines.
If there is not a special cable (BCC08) on serial port 3 (printer
port), and the optional video board is not present (or failed the self-
test), the system will then use the monochrome video as the system con‐
sole. All input/output destined for will use the monochrome video
instead. (This is done by overwriting the device switch tables.)
There is a second set of device switch entries configured that may be
used as an additional terminal, (hardwire, modem, or autodialer) con‐
nection, or user dial-up access. For further information, see
The Hold Screen key is supported. The Small VAX monochrome driver
treats this key as if CTRL/S or CTRL/Q is typed. Pressing the Hold
Screen key suspends the output if it is not already suspended. The out‐
put will be resumed by pressing this key again (if the output was sus‐
pended).
FilesSee Alsoss(4), ttys(5), MAKEDEV(8)
VAX sm(4)
