The AS/400 Advanced 36 model 236 was the first of the reduced-instruction-set- computer-based (RISC-based) systems marketed by IBM. Earlier this year, the AS/400 Advanced 36 model 436 was released. With the new boxes came new releases of the popular, proprietary System Support Programming (SSP) operating system, built on basic AS/400 packaging and technology. The RISC systems let S/36 customers move to a platform that provides the greater capacity, performance, and reliability of today’s technology without the need to migrate to OS/400. The Advanced 36 series offers complete object compatibility for existing S/36 applications. S/36-based applications can be upgraded to the faster hardware without digging up and recompiling old source code or retraining staff on a new operating system. The new hardware allows for increased DASD, memory, and internal tape drive capacity. In addition, many of the functions that had been priced separately as features on the original S/36s (e.g., 5360, 5362, 5363, 5364) were rolled into the total SSP release 7.5 package for the AS/400 Advanced 36 model 436.
The AS/400 Advanced 36 model 436 has the additional distinction of supporting SSP release 7.5, OS/400 V3R6 and higher, or multiple operating systems, namely OS/400 with up to three (but you can try more) guest SSP operating systems acting as independent entities on the OS/400 operating system. The SSP operating systems exist as objects within OS/400. To the user, a single AS/400 Advanced 36 model 436 configured with OS/400 and three guest SSP OSs will feel like an AS/400 and three S/36s. But of course, all four are contained within one box. The separate entities communicate as though they are connected via a LAN. However, since the entities are all contained on the same system, the networking scheme is correctly referred to as an Internal Local Area Network (ILAN). This article will highlight the use of PC Support/36 and Client Access/400 in the AS/400 Advanced 36 model 236 and 436 environments and discuss communications considerations for ILAN.
The S/36 model 5360 was introduced in 1983. Although that does not seem long ago, 13 years is an eon in the computer industry. PC Support/36 is a DOS-based application that features file transfer, shared folders, virtual print, and messaging facilities; the Workstation Feature; PC Organizer (PCO); and token-ring support. PC Support/36 was the predecessor to PC Support/400, which later became Client Access/400. PC Support/36 was intended for use on a DOS-based PC connected to a S/36 by token-ring, SDLC using remote 5250 emulation, or a non-SNA twinaxial workstation controller. Its router is a Terminate and Stay Resident (TSR) program that runs in real memory. A TSR program is one that occupies space in memory when started and does not release that space when ended. The memory can be cleared for use by another application only by an IPL. When TSR program memory is allocated in real memory (memory below the 640KB boundary in DOS), large, memory-intensive applications such as word processors and spreadsheets may fail when they are unable to allocate enough memory to run. In addition, the S/36 device drivers for shared folders are not supported for loading in high or extended memory. These two restrictions, which were minor considerations in the computing world of the early 1980s, are major limitations in today’s memory-intensive desktop computing environment.
PC Support/36 alone will not coexist with Windows. Windows’ heavy use of memory swapping pulls the pants right off of PC Support/36. PCSWIN protected the early versions of PC Support/400’s router from this problem, but that program does not work for the PC Support/36 router. There is a S/36 5250 emulation for Windows package that supplies a subset of PC Support/36 applications over twinaxial cable for the Windows user. It provides support for the PC Support/36 router with transfer function and, in most cases, virtual printing, but that is about it. PC Support/36 can be used from within a Virtual DOS Machine (VDM) on OS/2 if connectivity is established through token-ring, but if you are connected over twinaxial cable, it can be used only with Workstation Emulation (WSE). WSE is the 5250 emulator for IBM Microchannel PCs. Although PC Support/36 works with many 5250 emulators, WSE has its own 8088 processor on its PC card. Because the PC Support/36 application is run from the WSE card, when you hot-key in OS/2, PC Support/36 is not lost. No other 5250 emulator has this feature.
As new desktop technology emerged in the 1980s, IBM did not enhance the functionality of PC Support/36. Instead, IBM added the PC Support/36 Coexistence PRPQ (Programming Request for Price Quotation) to PC Support/36 in order to allow its S/36 base to communicate with SSP through PC Support/400 or Client Access/400 from the desktop client. The PRPQ lets SSP users maintain a modern desktop view of SSP. It also allows for communications over token-ring and SDLC and adds type-2 Shared Folders support to the S/36, giving clients concurrent access to both OS/400 and SSP folders. Unfortunately, the only SSP users who could take advantage of the PRPQ were those who already had AS/400s in their environments, since Client Access/400 is installed from a folder on the AS/400. There was also a little-known PRPQ shipped for the S/36 called SDLC Router, which was essentially the real memory version of the PC Support/400 SDLC router. This second PRPQ allows PC Support/36 applications to be run over a WAN without the use of remote 5250 emulation. There is a historic anomaly in PC Support/36 that provides a communications benefit for today’s S/36 user. Token-ring is APPC-capable on the S/36. However, unlike on the AS/400, twinaxial connections are not fully APPC-capable on the S/36. For this reason, PC Support/36 is configurable on a S/36 as an SSP-ICF communications option (see Figures 1 and 2), instead of as an application using SNA protocols (like its successor, PC Support/400). PC Support/36 has some APPC-like functionality, allowing it to operate transparently over token-ring or the non-
SNA twinaxial connections of the S/36. PC Support/400 differs from PC Support/36 in that the AS/400 version is a true application that uses SNA protocols to communicate. Despite, or perhaps because of this difference, PC Support/36 can fill a particular niche for the S/36 user. When a Client Access/400 router is started to the S/36, an APPC session is used. The S/36, unlike the AS/400, allows only a finite number of APPC sessions to be active at one time, which makes these sessions quite valuable. However, when a PC Support/36 router is started to a S/36, no APPC session is used, freeing the valuable APPC sessions for other communications tasks. While PC Support/36 has many limitations when compared to Client Access/400, it can be particularly useful for S/36 users with heavy communications needs. By choosing PC Support/36, router, file transfer, shared folder, messaging, and virtual printing activities can be performed without regard to the number of currently active APPC sessions.
On the AS/400, all features of PC Support/36—including PC Support/36 Coexistence—have been rolled into SSP release 7.5. This simplifies the installation process and allows the user to be immediately ready to use the Client Access/400 router. In addition, a version of Client Access/400 for DOS with Extended Memory can be installed from SSP, independent of the AS/400. This is an I-listed PRPQ called the DOS Client for SSP PRPQ. It was first made available for the S/36 user after the release of the AS/400 Advanced System 36 model 236. This particular PRPQ is packaged with the complete client portion of Client Access/400 for DOS with Extended Memory in an SSP folder along with separate PC installation diskettes, which are used to start the initial connection to the client. The PRPQ gives PC Support/36 users a licensed copy of the enhanced desktop features of Client Access/400 and can be used on the native S/36s as well as the Advanced Series machines. It brings all S/36 users a modern desktop view of SSP and compatibility with Windows 3.1. It also provides the user with the ability to use high memory as well as a program called Remove PC Support (RMVPCS) which is used to remove the Client Access router from memory. There is also support for providing coexistence with Novell and other LAN server applications. Additionally, the PRPQ lets S/36 users take advantage of the many Windows-based database applications for the S/36 that rely on the Client Access router.
With an AS/400 Advanced 36 model 436 running SSP as a guest on the OS/400 operating system, S/36 users can access all the SSP-supported features of Client Access/400 using standard AS/400 methods. SSP, because of the PC Support/36 Coexistence feature of release 7.5, can support three of the six Client Access/400 clients: Client Access/400 for DOS, Client Access/400 for DOS with Extended Memory, and Client Access/400 for OS/2. PC Support/36 Coexistence implements a corresponding subset of the functions provided by the OS/400 Client Access server. For example, PC Support/36 Coexistence does not support the remote command function, RUMBA/400, remote SQL, or the data queues function—a limitation of SSP rather than a PC Support/36 issue. (The exception to that statement is RUMBA/400, which was simply never implemented for the S/36.) The Client Access/400 features not supported for use by the S/36 are the GUI-ized version of Client Access/400 for Windows 3.1 and the 32-bit versions of Client Access/400 for Optimized OS/2 and Client Access/400 for Windows 95.
Running SSP as a guest on OS/400 also gives S/36 users a wider range of networking connectivity options. In the guest environment, communications between OS/400 and SSP are handled by an APPC- or APPN-based configuration of ILAN. If the connection to the AS/400 Advanced 36 model 436 is direct to OS/400, users can choose
from the whole range of client connectivity options supported by OS/400: TDLC, async, SDLC, token-ring, Ethernet, or X.25.
Direct connection to the S/36 or to the AS/400 Advanced 36 machine on OS/400 is limited by the communications options supported on the S/36. For example, the S/36 does not by itself support Ethernet or TDLC. Client Access/ 400 for OS/2 using Communications Manager/2 allows direct connectivity to the S/36 through token-ring, SDLC, or X.25. DOS Client Access/400 allows token-ring or SDLC connectivity.
The AS/400 Advanced 36 model 436 multiple operating system environment also allows direct connection to an SSP object with ILAN providing the communications between SSP and OS/400. This is accomplished by allocating an AS/400 hardware resource exclusively to an SSP object; the allocated line can then be used only by the S/36 it is allocated to.
The OS/400 ILAN communication configuration definition for the first AS/400 Advanced 36 machine’s connection is supplied with OS/400. When SSP is installed on the AS/400 Advanced 36 machine, a default ILAN configuration for the SSP side of the communications is supplied. The supplied defaults make the first ILAN connection a fairly simple matter. Using Display Net Attributes (DSPNETA) on OS/400, get the OS/400 control point name from the Local Control Point Name field. On the command line of the first AS/400 Advanced 36 machine you configure, enter CHGSYSVAL CTLPOINT,scpname, where “scpname” is the name of the OS/400 local system control point. This control point gives the configuration the first default APPC ILAN connection between OS/400 and SSP.
ILAN connections can be APPN rather than APPC, which simplifies the configuration of external devices such as PCs or other AS/400s but causes additional network traffic when topologies are updated. Since SSP is essentially limited to 150 nodes in its topology, configuring the S/36 as a Low Entry Node (LENNODE) is a more practical solution than configuring it as a NETNODE. Keep in mind that the S/36 cannot be configured as an ENDNODE. See
Figure 3 for the create controller description for connection to the Advanced 36.
Notice the Block ID for the exchange ID is 03E; that is the block identifier for the S/36.
To start a Router to the Advanced 36 machine, your CONFIG.PCS file might look something like this: SFLR 1,I,,AS400
RTYP ITRN
RTLN APPN.PC1
ADRS IBMM3601,AS400
TRLI AS400,400000000AE9
This configuration will allow a Client Access/400-supported router to be started to the Advanced 36 machine. The TRLI address is that of the AS/400, however, the ADRS essentially allows the router to pass through the AS/400 to the S/36.
When Client Access is to be used, the APPC mode called QPCSUPP needs to be available on both systems. The AS/400 configuration essentially consists of configuring a line, a controller, and a device. The S/36 equivalent is the command called Configure ICF (CNFIGICF), which creates a configuration of a line and a subsystem. Through CNFIGICF for APPC communications, each external communication device will be configured to appear as an adjacent device to the S/36. Essentially, CNFIGICF builds a routing table for APPC. The Remote System AS/400 with Remote Location AS/400 is already defined. (This is the definition of the attached AS/400.) Remote location name PC1 is being created for a PC that is either attached directly to the AS/400 or known by the networking topology of the AS/400. When APPC is used for the S/36, a table of devices
known by the adjacent AS/400 is created, allowing those devices to communicate to the S/36.
The Advanced System 36 series gives the midrange computing audience a low-maintenance, inexpensive operating system that responds pretty well to the needs of the modern desktop environment. SSP is a little short on features compared to the AS/400, but it is easy to learn and use and should not be overlooked when you conside which database system is right for your business environment.
Figure 1: Configuring the ILAN with SSP-ICF Figure 2: Configure ICF Routing Table
Figure 3: Create Ctl Desc (APPC) (CRTCTLAPPC)
More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.
TRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now! Request Now.
Forms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.
Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:
Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.
IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn:
LATEST COMMENTS
MC Press Online