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2.
The equipment drawer is closed.
3.
All interlocks are closed.
4.
The disk is rotating at 2400 rpm.
5.
No other condition prevents normal operation of the
disk.
The exact state is determined by examining the st~tus re-
sponse for the 510, HIO, or TIO instructions. Other I/O
instructions, TOV and AIO, provide additional status
indications.
DATA TRANSFERS
A data tTansfer may be initiated with an 510 instruction
when the following criteria are satisfied:
1.
The 1/0 address is recognized.
2.
The controller is in the ready condition.
3.
An interrupt is not pending.
If these criteria are satisfied, the controller enters the busy
condition and transfers data to or from the disk as specified
by the order (e.g., Read or Write), unti I the required num-
ber of bytes have been transferred.
When the operation
terminates, the controller returns to the ready condition.
The operation may also be terminated by
1.
An lOP halt, generated
by the lOP on some errors.
2.
An HIO instruction.
3.
An I/O Reset.
In the above cases, all data may not have been transferred
wl-ten the halt occurs.
Following an HIO instruction, an
I/O Reset, or an lOP halt, the controller is in the ready
conclition.
RECOMMENDATIONS
The following recommendations and suggested usage apply
to the Cartridge Disk System:
1.
The system is recommended for
a.
System, processor, and public library residence.
b.
Permanent storage of user-programs.
c.
Temporary storage of data.
d.
Permanent storage of data.
e.
Booti ng the system.
2.
In order to reboot the system, for example, cartridges
may be loaded and unloaded whi Ie the system is stopped
(the LOAD indicator on the operator control panel is
lighted).
3.
An operation cannot be initiated on a device when the
controller is busy; therefore, operations cannot occur
simultaneously on two devices. However, while one
device is busy, a
no
or a TDV instruction may be
issued to another device.
4.
New cartridges should be inspected for defects before
using, and existing cartridges must be handled care-
fully to prevent contamination, because on alternate
track is not assigned if a defective track is encountered
during I/O operations. (Inspection and handling pro-
cedures are detailed in Chapter 4.)
5.
While cartridges are being loaded
and
unloaded.,
it
is
not possible for the disk I/O program to access the
fixed disk on the same drive.
Recommendations
13
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