IBM System/360

2821 CONTROL UNIT
Commands
Bit
Command
0 3 4
Test I/O
0 0
0
Sense 0 0 0
No-op
0
0
Printer
Write
x x x x x 0 0
Control (Skip Space)
x x x x
x
1
Read (1404)
1 0 0
0
Reader
Read
y y y
0
0 0
Control (Feed)
y
y y
0 0
Punch
Write
z z z
0 0
0
Read (Punch Feed Read) z z 0 0 0
Modifiers
Bit
x x x x x
Printer 0 3 4
Space 1
0 0 0 0
Space 3
0
0
Skip to Chan 1
0
1
Skip to Chan 12
0 0
On Write, Carriage Operation is after Print. On Control, it is
immediate.
Bit
L___X__X
Reader
1
2
Data Mode 1 (Read)
y y
0
Data Mode 2 (Read)
y
y
Read & Feed & Stacker Rl 0
y
Read & Feed & Stacker R2
y
Read & Feed & Stacker RP3
y
Read (No Feed No Stacker Se!) 1
y
Feed & stacker Rl (Control)
0
0
1
Feed & Stacker R2 (Control) 0
1 1
Feed & Stacker RP3 (Control) 1 0
90 S/360
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