Xerox Alto I User Manual

.
I
.
I
0
1
2
3
4
5
6
7
10
11
Disk Address
. . . .
Command Seal (110B)
I I I I I I
Disk Command
. . .
Sector -1 if done
I I I
Disk Status
Pointer to next KCB
Disk status
Disk command
Header record memory address
Label record memory address
Data record memory address
No-Error Interrupt bit mask
Error Interrupt bit mask
Reserved
Disk address
Disk Command Block
(KCB)
Header
Action
I
Seek
Seek
Fail
521
522
523
524
:
.
.
Label Data
Action Action
I
0: Read
1: Check
2or3: Write
Not Data
Rdy Late
Idle
Pointer to next KCB
I
ChSm
Error
Status at beginning of sector
Disk address of most recent KCB
Sector interrupt bit mask
Reserved Page 1 Locations
Figure 8 -- Disk Data Structures
Rst
No
Drive
Xfer
Completion
Code
I
0: Good status
1: Hardware error
2: Check error
3: Illegal sector

Xerox Alto I Specifications

General

Brand	Xerox
Model	Alto I
Category	Desktop
Language	English