BACK
If you select the Edit System Characteristics entry on the Main Menu, the System Builder displays the System Characteristics Menu, which lists the run-time system characteristics of the system you are building. Figure 3-3 shows this menu.
Descriptions of the entries on the System Characteristics Menu follow:
• System image - Specify the name of the system image file. If you specified a file name with the jSYSTEM qualifier in the EBUILD command, the System Builder displays that name here as the default.
Otherwise, the System Builder displays the name of your data file with a SYS file type as the default.
Figure 3-3: System Characteristics Menu
System SAMPLE-IMAGE - Editing System Characteristics System image
Debug Console
Local Remote Both None Yes No
Instruction emulation String Float Both None
Boot method Disk ROM Downline
Disk/volume names Guaranteed image list Number of jobs 16 Number of subprocesses 48
Ports 256
Pool size 384 blocks
PO Virtual size 1024 pages
P1 Virtual size 128 pages
Interrupt stack 2 pages
System region size 128 pages Dynamic program space 0 pages Time interval 10000 microseconds
Connect time 45 seconds
Memory limit 0 pages
EPA Yes No
DO
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HELP BACK• Debug - Select Local to include the debugger image EDEBUGLCL in the system image. Select Remote to include the remote debugger EDEBUGREM in the system image. Select Both to include both debuggers. When you include both debuggers, EDEBUGREM is the primary debugger; EDEBUGLCL gains control only if a fatal system error occurs. The default is Remote. For more information on the debuggers, see Chapter 5.
NOTE
You might want to include a debugger during the devel-opment of a system. You can select a debugger even if no program has the Debug option. The selected debugger gains control if the program does not handle an exception.
• Console - Select Yes to allow communication with the console terminal on the target machine. The System Builder includes the appropriate console driver and device description. If you select Local or Both for the Debug option, the console driver and device description are automatically included. The name for the system's console terminal is CONSOLE:. If you select No with the debugging option Remote, the remote VAX/VMS terminal behaves as the console terminal, when running the remote debugger. The default is Yes.
• Instruction emulation - This entry selects emulation software for instructions present in the full VAX architecture but not present in the MicroVAX architecture. Select None unless you are building a system for a Micro VAX target machine. If your target machine is a Micro VAX I, MicroVAX II, or KA620, you must select String to include emulation software for string instructions in the system. Float is optional. If you select Float, the System Builder includes emulation software for the extended-precision floating-point instructions. Selecting Both includes emulation software for both groups of instructions. The default is String.
You can choose the double-precision format in VAXELN Pascal and C programs by using the compiler qualifier /NOG_FLOATING, and you can choose the default double-precision format of the run-time library with the command procedures DFLOATRTL.COM and GFLOATRTL.COM. By using these qualifiers and command proce-dures, you can omit the slower floating-point emulation software.
• Boot method - This entry indicates the method by which the system is to be booted on the target machine. Select Disk if the system is to be loaded and booted from a disk or tape device. Select ROM if the system is to be loaded and booted from read-only memory (ROM).
Select Downline if the system is to be down-line loaded. The default is Downline.
The Boot method characteristic specifies one of the following to be the type of image header used in the system:
Disk not specified a node address, the System Builder displays a warning message.
• Disk/volume names - Supply device specifications and volume names in the following format for volumes present on the target
OPEN(FILE1,FILE_NAME := 'DISK$TEST1: [RT.SRC]RXDRlVER.PAS')
Separate multiple quoted arguments with commas. The first speci-fication identifies the default volume. The File Service mounts the indicated volumes when the system is booted. The volume name is optional; if you omit it or specify a volume not present in the drive, the File Service attempts to mount the volume that is present in the drive.
An alternative to specifying volume names on this menu is to use the MOUNT_VOLUME procedure, which also mounts the volume present in the drive, if you omit the volume name.
• Guaranteed image list - Specify a list of shareable images that are referred to by programs loaded by the dynamic program loader.
Shareable images that are referred to by programs included in the system by the System Builder are included automatically. But share-able images referred to by programs that are not loaded until run time would not otherwise be included.
• Number of jobs - Specify an integer in the range 1 to 32767 to indicate the maximum number of jobs that can exist in the system at anyone time. The number includes both user and system jobs, for example, device drivers. This value is used to determine the number of PO page table slots reserved in the system. The default is 16.
• Number of subprocesses - Specify an integer in the range 1 to 32767 to indicate the maximum number of subprocesses that can exist in the system at anyone time, including both user and system subprocesses. This value plus the number of jobs is used to calculate the number of PI page table slots to be reserved in the system. The default is 48.
NOTE
Overestimating the number of jobs or subprocesses intro-duces negligible overhead into the system. For each job specified, two bits are allocated in a system bitmap; for each subprocess, one bit is allocated.
• Ports - Specify an integer in the range 2 to 32767 to indicate the maximum number of message ports the system can use simultane-ously. The default is 256.
• Pool size - Specify an integer in the range 16 to 32764 to indicate the number of blocks necessary to store the kernel objects the system uses Simultaneously. Each kernel object in use requires one block, processes require three blocks, and each job requires a few additional blocks. Pool blocks are 128 bytes long. The default is 384.
• PO Virtual size - Specify an integer in the range 128 to 32640 to indicate the maximum number of 512-byte pages that each PO region in the system occupies. The kernel uses this value to allocate page tables for each job. The default is 1024. If the value supplied is not a multiple of 128, the System Builder will round it up to the next multiple of 128.
Demands on PO memory arise from the following sources:
• Program images (variables at the outer level and all code)
• Heap data and other dynamically allocated memory
• Created and received messages
• Accessed AREAs
• Accessed FORTRAN Commons
All PO pages that are set up for a job at build time appear under the job's program information entry on a full EBUILD map. These PO pages include any demand zero pages that are not stored in the system image on disk. Also, the Pascal NEW procedure dynamically adds to the heap.
• PI Virtual size - Specify an integer in the range 128 to 32640 to indicate the maximum number of 5I2-byte pages that each PI region in the system occupies. The kernel uses this value to allocate page tables for each process created in a job. The default is 128. If the value supplied is not a multiple of 128, the System Builder will round it up to the next multiple of 128.
Demands on PI memory arise from the following sources:
• The user stack
• The kernel stack
• The process-context page
All process-local variables (those declared inside a block) are placed on the user or kernel stack in PI space, depending on which mode the process is running in. Variables declared within the Pascal PROGRAM block and the C main or first function are process-local variables for the master process of a job. Furthermore, all call frames are placed on the appropriate stack.
NOTE
The PO and PI virtual size parameters are used as the maxi-mums for all jobs and processes in the system. Therefore, if anyone job or process requires a large virtual PO or PI size, every job or process in the system will have that amount as its maximum virtual memory size. On rtVAX systems, this can cause a problem.
Because rtVAX systems require that all memory for page table entries be contiguous in physical memory, overesti-mating the PO or PI virtual size can create much greater overhead than on other systems. When each job's page table is set up, memory for page table entries is allocated all at one time and cannot be expanded dynamically.
Therefore, when each job is created, sufficient physical memory is allocated for the page table entries for both the PO and PI virtual sizes specified on the menu. When each subprocess is created, sufficient physical memory is allocated for the PI virtual size specified on the menu. If more virtual memory is specified than is needed, memory will be wasted to provide page-table entries for that unused space.
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Overestimating the PO or PI virtual size on non-rtVAX sys-tems causes little overhead, since physical memory for page table entries is allocated dynamically. If memory within the virtual space specified is not required, no memory for page table entries for that space will be allocated.
Interrupt stack - Specify an integer in the range 2 to 8192 to indicate the maximum number of pages required for the system's interrupt stack. The default is 2.
System region size - Specify an integer in the range 0 to 32767 to indicate the maximum number of pages required by interrupt service communication regions and, if selected, the performance analyzer and error-logging buffers. The kernel uses this value to allocate page table entries for the system during the system's start-up. The default is 128.
Dynamic program space - Specify an integer in the range 0 to 32767 to indicate the number of memory pages the kernel can allocate for loading programs dynamically into the running system. The default is O.
Time interval - Specify an integer in the range 1 to 120000000 (mi-croseconds) to indicate the interval between interval timer interrupts.
The value you specify is the minimum time that can be used for time-dependent operations. Each interrupt increments the system time and starts time-dependent scheduling in the system. On some processors (including the MicroVAX), you cannot alter the time interval. The default is 10000.
Connect time ' - Specify an integer in the range 1 to 3599 to indicate the seconds allowed to elapse before a circuit connection must be accepted. The default is 45.
Memory limit - Specify an integer in the range 0 to 65535 to indicate the amount of physical memory in pages that is available for use by the system. The default is O. If you specify the default, the system will use all the memory available on the target configuration.
You need to specify a limit only in special applications, such as for a system that contains a multiported memory. The multiported memory would be configured at the top of memory, and the system size you specify would not include the multiported memory. In that case, the kernel would not allocate any multiported memory for general needs. You can still use the ALLOCATE-MEMORY or ALLOCATE_
SYSTEM_REGION services to access this memory.
• EP A - Select Yes to allow the collection of performance data for the system. The System Builder includes the VAXELN Performance Utility Collector. The default is No. For more information on the VAXELN Performance Utility, see Chapter 6.