3.2. Operating System
The following section describes compatibility issues that affect the UNICOS operating system beginning with the 10.0.0.4 release.
3.2.1. Memory HIPPI Not Supported on Model V based Systems
The UNICOS 10.0.0.4 release does not support memory HIPPI on Model V based systems.
3.2.2. Data Cache Disabled on Revision A CPUs
Data cache is disabled by default on CRAY SV1 Revision A systems. (See Section 1.3.1 for more information on Revision A CPUs.)
Warning | Enabling cache is not supported on Revision A CPUs and doing so could cause undetected memory corruption and system hang conditions. |
If your site needs to enable cache for benchmarking purposes, contact your Silicon Graphics support representative.
See the sv1cache(7) man page for more information.
3.2.3. CRAY SV1 Specific Software Required
CRAY SV1 Revision A CPUs require CRAY SV1 specific software packages (including asynchronous software products). (See Section 1.3.1 for more information on Revision A CPUs.)
Revison A modules are not binary compatible with other Cray PVP systems. Therefore, all applications must be recompiled before running on Revison A CPUs. Contact your Silicon Graphics support representative for more information.
3.2.4. CPU Diagnostics Supported Only on Mixed CPU Systems
The online CPU diagnostics are supported only on CRAY SV1 systems with mixed CPUs. These diagnostics will run only on CRAY J90 and CRAY J90se CPUs in a mixed system. They are not supported on CRAY SV1 Revision A CPUs.
The following online CPU confidence tests are not supported:
| olcfpt(8) |
| olcm(8) |
| olcrit(8) |
| olcsvc(8) |
| olibuf(8) |
| olsbt(8) |
The following online CPU maintenance tests are not supported:
| olyfpt |
| olyscl |
| olyvpt |
3.2.5. /etc/shutdown.sh Script Changed
Between UNICOS 9.0 and UNICOS 10.0, the /etc/shutdown.sh script was changed to address problems seen at some sites in which users needed a user exit prior to shutting down the network from the mainframe. The change adds support for an /etc/shutdown.mid script. This script could be useful to sites that have NQS jobs that are being taken care of on NFS disks.
The script will be called after all user processes have been stopped, but the networks are still up. For more information about this change and the options available for the shutdown process, refer to General UNICOS Administration.
3.2.6. /etc/cpu Command Options Added
Several new options have been added to the /etc/cpu(8) command to provide greater control over program behavior and cache usage on CRAY SV1 Revision A systems. Two of the new options are intended for general use:
Example:
mfel5% cpu -i cpu type state 0 sv1 up cache defon 1 sv1 up cache defon 2 sv1 up cache defon 3 sv1 up cache defon 4 sv1 down cache defon 5 sv1 up cache defon 6 sv1 up cache defon 7 sv1 up cache defon |
| -x cputype | Selects a CPU type. Tells the kernel to run a command on a certain type of CPU in a mixed CPU system. One or more CPU types may be specified. Valid cputype arguments are:
The -x option may not be used with the old CPU mask specifier ( /etc/cpu a command) nor may it be used with the -n option. If the binary is not CRAY SV1 Revision A safe, using the -x SV1 flag alone will not force execution in a CRAY SV1 CPU. If this is attempted, the execution of the unsafe binary will fail. |
Examples:
/etc/cpu -x sv1 command |
Runs command on any CRAY SV1 CPU in the system, but not on any other type of CPU in the system.
/etc/cpu -x sv1,j90se command |
Runs command on any CRAY SV1 or CRAY J90se CPU in the system.
Two of the new cpu command options are intended for administrator use only:
| -e enforcement | Allows administrator control over the CRAY SV1 Revision A safe enforcement feature. |
CRAY SV1 Revision A systems do not implement the exact same memory ordering guarantees as previous systems. Executables run on CRAY SV1 Revision A systems must have the code corrected to properly execute on the system. Programs that have the necessary corrections are designated as Revision A safe binaries. Programs that do not have these corrections are known as unsafe binaries.
All executables must contain either the CRAY SV1-memory-ordering-patch (moc) or the CRAY SV1-all-rw-patch (arw) to be Revision A safe. In addition, any executable which attempts to multi-task ( tfork(2)) with data cache enabled must also contain the CRAY SV1-aligned-cmr-semts-patch (act) to be considered safe. The file(1) command can be used to determine which patches an executable program contains. See the sv1cache(1) man page for more details on patches.
To prevent memory ordering problems, the UNICOS kernel will automatically check all programs run on the system for the necessary code correction. This check takes place during the execution (via the exec(2) system call) of an executable. If the program does not have the necessary patches (either moc or arw), the executable will fail.
The kernel will also check a multitasking program run with data cache enabled for the necessary code correction. This check takes place during the tfork system call when a code begins to multitask. If the program does not contain the necessary patch (act), the tfork will fail.
Situations may occur where a system administrator wishes to temporarily disable this kernel Revision A safe enforcement. This option provides a mechanism to do this.
| Warning | CRAY SV1 Revision A systems are not supported when running with kernel Revision A safe enforcement turned off. Also, if enforcement is off, a multitasking program without the act patch will be allowed to run. This can result in a hung CPU that will require a system reboot to clear. |
Valid enforcement options are:
| def | Turns on CRAY SV1 Revision A safe enforcement (the default setting for all Revision A systems). | |
| off | Turns off CRAY SV1 Revision A safe enforcement. Note that CRAY SV1 Revision A systems are not supported when running in this mode. |
The following example turns off CRAY SV1 Revision A safe enforcement:
/etc/cpu -e off |
The following example turns on CRAY SV1 Revision A safe enforcement:
/etc/cpu -e def |
The other new option intended for administrator use is as follows:
| -f | Forces execution of an unsafe binary even when CRAY SV1 Revision A safe enforcement is turned on. When specified with the -x SV1 option, this option can be used by the superuser or a user with PRIV_RESOURCE to override the kernel CRAY SV1 Revision A safe enforcement and allow an unsafe binary to run.
The -f option cannot be used alone. It must be used with -x sv1. |
The following example runs an unsafe command despite the CRAY SV1 Revision A safe enforcement being on:
/etc/cpu -x SV1 -f command |