ginning in register d,
using tape unit 10, j is unknown. The program begins in register
enteread.

enteread mec ,clear flags initially
mrb 1000 ,730000001060
dzm x ,put zero in memory location x
e mps
jmp outcheck
dio x/d ,store in location modified by x
snx x/+1 ,add 1 to C(x)
jmp e

outcheck mec ,examine flags
spi ,end of record?
jmp recordend ,yes
hlt ,error

recordend snx x/+1 ,to find value of j
" ,resume programming C(IA) = j
"
"
"

_Forward Spacing_

Forward spacing is done by giving an MRB or MRA order. This moves the
tape forward with the read-write head positioned at the end of the
following record. If n read orders are given, the tape is spaced forward
n records. By giving the MEC order, parity flags are examined to see
that information on tape has been read correctly.

_Backspacing_

By giving an MBA or MBB order the tape is moved backwards a record with
the read-write heads positioned in the previous end of record gap. The
end of record flag is set when the tape has moved backwards a record.

_Rewinding_

Rewinding is accomplished by giving the rewind order, move tape to load
point, MLP. The rewind order starts a unit rewinding and does not tie up
the TC. If a motion command is given which calls for a unit that is
rewinding, the command is executed, but the action will not take place
until the unit is available.

_Unit Availability_

A unit is unavailable to the program under the following conditions:

1. Unit is rewinding.
2. Tape is improperly loaded.
3. Cover door open.
4. Unit overloaded.
5. Unit under manual control.
6. Power off.

A selected but unavailable unit holds up the TC if a motion order is
given for the unit. The TC will be held up until the unit is ready.

_Flag Positions_

_IO Bit_ _Flag_

0 EOR - End of record
1 RWF - Read-Write
2 EOT - End of Tape
3 Parity

_Connection with High Speed Channel_

The high speed channel directs the tape control, and word transfer, just
as a program would. A unit is first started reading or wr