ECMWF uses multitasking for the operational forecast, and at the same time we run both STATIC production because they don't function easily wi thout the new LOADER.
Having to look after so many compiler/library combinations requires much effort, in particular when users by accident pick up non-matching versions and then come to user support and ask for help.
Cd) Compatibility
We feel that CRI is not paying sufficient attention to the problems of compatibility between releases. We mention two examples: First, CFT 1.14 BF2 will not produced library routines that avoided TASK COMMON in a 1.13 environment. And second, the
(ii) Conrad Kimball (Boeing) (a) Software Configuration
Boeing Computer Services (BCS), a division of The A130 driver for our HYPERchannellocal network.
(b) X-MP Installation unadvertised vector recursion facility of the 115.
Sin~e we were about to convert to COS 1.12, we
interactive facility has also tremendously improved the productivity of our test sessions. our environment, with extremely limited test time availability, we simply cannot function without CSIM.
Lest all th.is sound like everything went smoothly, we we are encountering include: massive internal changes between COS 1.12 and COS 1.14; untested code in 1.14; undefined variables in the CFT sections of some 1.14 utilities; and 90 unresolved SPR's for which we had previously submitted corrective code (we expended at least one man-month just converting SPR
In addition to these blatant bugs, we have also found appropriate changes to the source management tool's internal text file, and finally use UPDATE to change documentation (although the 1.15 pre-release letter was very good). philosophy of fault tolerance and damage containment must be pursued.
Fifth, Cray Research should provide various data center assistance items for their sites. BCS would like to see hooks (user exits) through COS; better scheduling of large jobs (increasingly important as memory sizes grow); a fast, dynamic SSD pre-emption restore the original production environment.
(iii) Mostyn Lewis (Chevron)
As Chevron Oil Field Research Company (COFRC) took delivery of an X-MP/48 in May 1985, it was necessary to convert to COS 1.14 to support the new hardware (four CPU's, extended addressing, 00-49 disks) and CFT 1.14 also, (to use scatter/gather hardware, for example). Our major problems occurred in CFT, VBS tape support and MVS station support.
CFT had one major and eight critical SPR's.
Programs ceased to vectorise; there were "compiler errors" (programs causing compiler aborts); bad code generation and a delay in fixing these problems (in was a further compounding of mis-communication when Cray actually believed they had fixed our problem when we were still suffering. A letter from our site analyst was necessary to prompt Cray into a realization of the unsatisfactory support before a final visi t found the bugs and cured them. The VBS problem had remained critical for three months.
The MVS Cray station had 12 significant problems.
All were fixed by local expertise and included an operation console "hang" problem and another which only allowed a maximum of three active streams (out of 16).
In summary, we believe we observed a breakdown in the communication link from the Cray Region to Field Support to Software Development. Mendota Heights seem to lack the awareness of a customer in
Let's have stability before features, please!
B. COS Interactive: A Developer's Perspective Bryan Koch (CRn
1. Overview
This paper briefly describes the functional characteristics of COS interactive, as available through the Station protocol. The applicability of COS interactive to the systems development process is discussed, and the availability of the interactive protocol in various Cray-supplied stations is described.
The majority of the paper is a walk-through of a sample interactive session, using Cray's CSIM simulator. interactive environment. Control statements are identical in the two modes; procedure ($PROC) files user's terminal (via the station). Control statements are also obtained from the user, via the station, pertain specifically to interactive sessions.
Nonetheless, it is possible to some degree to tune the system for interactive processing.
Two levels of scheduling affect interactive users, CPU and memory. Interactive users can be assigned to a specific job class, allowing them to be assigned a different priority than other classes of jobs. (In Mendota Heights, interactive jobs are assigned priority 8, while all other jobs execute at priority 7 or below.) This priority can be used to control the location of interactive jobs in the memory request queue.
2.2.1 Memory Scheduling
All other things being equal, the priority of a job control statement and interactive I/O request which results in a suspend. For a system wi th free memory, this can result in very snappy response times; when jobs must roll out to accommodate .the newly-resumed interactive job, the response time depends on the speed of the swap storage and the
2.3 Resource Utilization for Interactive Sessions
Unlike batch jobs, interactive sessions do not begin with a JOB statement. One implication of this is that interactive jobs cannot request any controlled devices, and are bound to use site-wide default limits for other resources.
Thus, interactive jobs cannot typically make use of on-line tapes, because reservations for tape drives must be declared on the JOB statement. Similar
The Station protocol supports two separate paths from a station user to the interactive session: data and control.
The 'data' path is used for interacting directly with the control statement processor or an application program. It supports ASCII characters, transparent 8-bit characters, as well as a special 'end of file' indicator.
The 'control' path allows the user to bypass normal flow control mechanisms and interact directly with the station and SCPo Control path requests allow the user to:
*
Determine the STATUS of the interactive session.Status information includes the last control statement executed, the CPU status (waiting, executing, suspended), and the amount of CPU terminating the interactive job.
*
Send an ABORT or ATTENTION interrupt to the currently-executing process. Abort and attention are similar, and many programs and users use them interchangeably. Both may be intercepted by the reprieve mechanism.Some programs terminate only on ABORT interrupts, and use ATTENTION interrupts to merely suspend their current activity and issue a prompt to the user. CSIM is an example of a program which selectively uses these two flavors of interrupts.
4. Availability
COS interactive is available through the Station protocol with almost all levels of COS used in the Cray community today. Cray-supplied stations which currently support interactive sessions include: