file: \wpfiles\vlbi\command_meanings jbh 05 Nov. 2002

Selected "pass" and "track" commands and their meanings

(text in italics taken from SNAP command manual)

Command, Meaning

tapeform: Sets up a numbered list of headstack positions ( in microns). These position numbers are commonly referred to as "pass" numbers, even though they may be executed in any

order.

Syntax: tapeform=pass,offset,pass,offset, ...

Response: tapeform/pass,offset,pass,offset, ...

Note that here "pass" means position.

trackform: Assigns a data source to each head

Syntax: trackform=track,sampler,track,sampler, ...

Response: trackform/track,sampler,track,sampler, ...

Note that here "track means" head. "Track" (head) is a number from 2 through 33, (102 through 133 for headstack 2) and "sampler" is a source such as 09us, which means baseband converter 09, upper sideband, sign bit. These assignments are sent to the formatter, which has an output driver for every head in every headstack.

tracks: (pre)Enables the output drivers in the formatter; the action is taken later when a "form=m" command is issued).

Syntax: tracks=list

Response: tracks/list

Note that here "track" means formatter output driver (or head).

Example1: tracks=v0,v1,v2,v3 (turns on heads by groups)

enable: Enable write drivers in the recorder

Syntax: enable=track1,track2, ... trackn

Response: enable/track1,track2, ... trackn

Note that here "track" means write driver (or head).

Example1: enable=g0g1,g2,g3 (turns on formatter drivers by groups). For a head to be on, it must be enabled both at the formatter (using tracks=...) and at the recorder (using enable=...).