IBM System/360 Operating Guide

SYSTEM POWER-ON AND POWER-OFF
Power to all system units is brought up during a
system power-on sequence. If power cannot be
successfully brought up on an I/O unit that is on-
line to the CPU, the system power-on sequence
cannot be completed. See the Operator's Control
Panel section.
PROGRAM LOAD ROUTINE
Prepare the I/O unit from which the program is
to be loaded as follows. (Refer to the appropriate
Systems Reference Library publication for infor-
mation concerning the particular I/O unit involved.)
Card I/O Unit Preparation
When the program to be loaded is contained in
punched cards, a card reader must be initialized.
The following steps generally apply to all card
readers:
• Run the cards out of the read feed by performing
a nonprocess runout as described for the par-
ticular card reader.
• Place the program-load deck in the read-feed
hopper.
• Press the reader start key.
The card reader is now ready to read the program
deck.
Disk I/O Unit Preparation
When the program is to be loaded from a magnetic
disk unit:
• Turn the disk-drive meter switch on. This
allows the device to be used for input/output.
• Place the disk pack containing the desired
program on the disk drive and operate the disk-
drive start key.
The disk storage unit is ready when its ready light
is on.
SYSTEM OPERATIONS
Tape I/O Unit Preparation
When a magnetic tape unit is being used to load
the problem program:
• Open the tape unit door for access to the tape
reels and read/write assembly.
• Place the tape reel containing the program on
the left reel hub and lock it in place.
• Thread the tape along the tape path and onto
the take-up reel.
• Wind the tape until the load- point marker is
well past the read/write head.
• Close the access door.
• Press the load-rewind key.
The tape unit is now ready to be used as input when
called on by the program-load routine.
Console Operation (Program Loading)
With the system power on and the appropriate I/O
load unit set up:
1. Set the address of the I/O load unit that contains
the program to be loaded in rotary switches G,
H, and.J (see Figure 2, OCP section). The
channel address is set in s'vvitch G; the unit
address in switches Hand J.
2. Make sure that the ROS Control, Rate, Address
Compare, and Check Control switches are all
in the PROCESS position (see Figure 2, right
center section). The Test light on the OC P
portion (see Figure 2) of the 20:30 console is
off only when all four of these switches are in
the PROCESS position.
3. Press the Load key on the OCP portion of the
2030 console. The Load light (see Figure 2,
OCP section) turns on when the Load key is
pressed, and it turns off after the load routine
has been completed (when the loading of the
new PSW has been completed).
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IBM System/360 Specifications

General

Brand	IBM
Model	System/360
Category	Desktop
Language	English