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storing it (LCW) in hex address 80, and then enter-
ing the execute LCW kernel in ROS (Figure 15).
Maintenance operations initiated by the diagnose
instruction may be divided into two main catagories
as follows:
1.
Execution of special kernels (maintenance
routines) in ROS (Figure 14). ROS mode FLT's and
Progressive Scan make extensive use of some of
these kernels.
2. Execution of any microinstruction, or subset
of microinstructions, in any desired order. This
procedure may be used to examine any specific area
in ROS. See Figure 22 for examples.
The diagnose instruction must be located on a
fullword boundary in main storage if additional
LCW's are to be used. When other LCW's (in addi-
tion to the one built by diagnose) are desired, they
must be located in main storage starting at the full-
word address immediately following the diagnose
instruction. Because IAR is used to c:ount up and
scan-out subsequent LCW's, any control logic func-
tion or malfunction that affects IAR content affects
the sequence of the stream of LCW's.
Diagnose is initiated and decoded in I-fetch like
all other System/360 instructions. When a control-
ling LCW contains the address of the entry to I-fetch
kernel (FB9), normal operations (System/360 in-
structions) will be resumed.
FAULT LOCATING TESTS (FLT's)
Fault locating tests (FL T's) are a series of semi-
automatic diagnostic tests that contain fault locating
abilities. The fault location ability of FLT's is an
additional step beyond the fault detection ability of
most diagnostic programs. After detecting a failure,
FLT's point to the probable cause(s) of the failure
through the use of a scoping index called Scopex.
FLT's and their supporting documentation are pro-
duced by computer programs that operate on data
extracted from the design automation logic master
tape.
Main Storage
Location
WWW
xxxx
Program Words
83020F2A
yyyyyyyy
zzzzzzzz
0400XXXX
ooooxxxx
00001 F72
47FOOWWW
Function
load l and R Regs (via scan - in kernel)
!lump
Addros1 Eocn Byte}
Specified Doto
Store Data in Bump
LCW1i
Read Data from &..mp
Exit to l·fetch
Bronch
On
Condition Bock to Begir.ning
{
Bump Wo<d 00 Use 1
F6A
Bump Wo<d 01 Use 1
E6A
Bump Wo<d 10 Use 1
F68
Bump Word 11 Use 1
E68
FIGURE 22. DIAGNOSE USAGE (SCOPE BUMP WOP.D)
The actual FLT's for the Model 50 are the ROS
mode zero and one-cycle tests. Various areas
(controls, registers, and circuits, etc.) must be
operating correctly before these cycle tests can be
run. Most of these areas (defined as hardcore) are
checked out first in the hardcore tests.
In
addition,
all of read only storage (ROS) is tested for address-
ing and content by the ROS bit tests. All tests for
the preceding items are contained on the Model 50
FLT tapes (Figure 23). These tests (hardcore, ROS
bit, and FLT's) are also available on disk packs.
See Figure 24.
Main Store Mode Tape
A) MS Mode Hardcore Tests:
l. Binary trigger: re$et off.
2. Address first 4096 words of MS.
3.
Binary trigger: step on and off.
4. All ROAR bi".
5.
ROS group readout.
6. ROS parity check circuits.
B) MS Mode ROS Bit Te1t1:
1. All ROS words for addressing
and content.
ROS Mode Tope
A) ROS Mode Hardcore Tests:
1.
Swit'h
from MS
mode to ROS mode.
2. Test the fol lowing:
Progressive scon stat (via ROS
scan-in kernel),
supervisory
stat,
sequence counter,
supervisory enable storage stat,
log trigger, pass trigger, fai
I
trigger, scan test counter, microorder
HA-A, ROS scan-out kernel,
zero-eye le poss test, and zero-cycle
fail test.
3.
Reset'l/O interface register.
FIGURE 23. FLT TAPES: MODEL 50
Disk Pack 1
MS Made Hardcore Tests
MS Made ROS Bit Tests
(ROS Planes 0-5)
Disk Pack 2
MS Made ROS Bit Tests
(ROS Planes 6- B)
Disk Pack 3
MS Made ROS Bit Tesh
(ROS Planes C · F)
Disk Pack 4
ROS Made Hardcore Tesh
ROS Made Cycle Tests (FLT's)
B) ROS Mode Cycle Tests (FLT'1):
1. Zero-<:ycle tests; all storage elements
for which scan-in (via odder out bus
or emit field) and scan-out paths exist.
2.
One-cycle tests os follows:
Seg
1: l, F, 0, 1/0,
earrystat,
PSW
(32-39), ond MVFR.
Seg 2: R, H, GP stats, and half sum.
Seg 3: M, Gl, G2,
J,
l sign, R Sign,
l syllable op, refetch, and
error (U, V).
Seg 4: Full sum, carry, and mover-out
errors
(2 cycle tests).
Seg 5: LSAR ond LSFR.
Seg
6:
ROAR
(2
cycle tes
~).
Seg 7: LB, MB, MO, Gl, G2, error
cheeks, and LB-MB parity
cheek.
FIGURE 24. FLT DISK PACKS: MODEL 50
Maintenance Features
(3/71)
41
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