[Info-vax] Changed Boot behavior on XP1000 since 2013

[MichaelM]

You can  read the hwc on XP1000; :

>>> e -b toy:0 -> secs
       e -b toy:2 -> mins
       e -b toy:4 -> hrs
       e -b toy:7 -> date
       e -b toy:8 -> month
       e -b toy:9 -> year offset

or together without secs
       e toy:2 -w -n 3
shows 4 (-n 3) halfwords (-w) beginning with address 2 (toy:2).

So we have made some tests on our XP1000 and have noticed:

>>> e toy:2 -w -n 3 shows the hwc time correct beginning with minutes and using year 2000 as base time (tested for years 2012 and 2013).
After an >>> INIT on the boot prompt or after a power off (poweroff
results in an INIT), the firmware changes the year byte if the byte is
greater than 0C (0C -> 0C, 0D -> 5D, 10 -> 60).

The hwc on our XP1000 shows this behavior:

VMS time 31.12.2012 23:45      2  772E       2E = 46 minute
                                               4  BB17      17 = 23
hour
                                               6  1F02       1F = 31
Day
                                               8  0C0C       0C = 12
Month
                                                                  0C =
12 Year + 2000 = 2012

 after Poweroff                           2  7732        32 = 50
                                                4  BB17
                                                6  1F02
                                                8  0C0C

after Poweroff for ~ 25 min          2  7712        12 = 18 minute
                                                4  BB00       00 = 00
hour
                                                6  0103        01 = 01
Day
                                                8  5D01        01 = 01
Month
                                                                   5D
= 93 Year + 2000 = 2093 ?

boot with                                   2  770A         0A = 10
25-jan-2013 14:05                      4  BB0E        0E = 14
after shutdown                           6  1903         19 = 25
                                                8  0D01         01 =
01
                                                                    0D
= 13 Year + 2000 = 2013

>>>INIT                                     2  770D         0D = 13
                                                 4  BB0E        0E =
14
                                                 6  1903         19 =
25
                                                 8  5D01         01 =
01
 
5D = 93

boot with 31.12.2012 23:50          2  7737         37 = 55
                                                 4  BB17        17 =
23
                                                 6  1F03         1F =
31
                                                 8  0C0C         0C =
12
 
0C = 12

after 10 minutes                          2  7700          00 = 00
                                                 4  BB00         00 =
00
                                                 6  0104          01 =
01
                                                 8  0D01          01 =
01
 
0D = 13    ,  after >>>INIT  0D -> 5D.

We have noticed too, that after year 2041 the time stays correct after
an INIT, so only years between 2013 and 2040 (28 years) seem to be
affected.