Integrated PC Servers

In Chapter 10, we saw how an IOP with its specifically designed, real-time operating system can perform device-control functions. Device control was the original intended use for IOPs, but it is not the only use. Because all IOPs are intelligent processors and can support different functions and even different operating systems, it was only a matter of time before IBM began to use one or more of these IOPs to run other types of applications. In the past few years, we have introduced the AS/400 special-function IOPs that provide more than just device support. These IOPs perform such special functions as RAID-5, fax, wireless network, and AppleTalk support. A natural extension has been to use IOPs to perform still other types of applications, including server applications.

In 1994, IBM announced the first of these server applications running on an IOP as the File Server I/O Processor (FSIOP). The FSIOP was a double-wide card that plugged directly into the AS/400. The card contained an Intel 486 processor, along with its own memory. Other I/O devices, including disks, were shared with the AS/400. The FSIOP card supported one or two LAN ports, with up to 255 users per port. Either Token-Ring or Ethernet LANs could be attached, and more than one of these file server cards could be plugged into the AS/400.

The operating system for the FSIOP was OS/2, although the customer never saw or dealt with this operating system. The AS/400 managed all the interactions with OS/2; the customer saw only the file server applications. OS/2 LAN Server was the first file-server application we announced. We added NetWare and Lotus Domino later.

It was obvious that we could use the FSIOP for more than just file serving, so we changed the name to the Integrated PC Server (IPCS) and later introduced new models of the IPCS with more powerful Intel Pentium processors and larger memories. With Version 4, we have upgraded OS/2 to Warp Server and have added new applications, such as Flowmark Workflow.

The benefits of the IPCS under the covers of an AS/400 are many. First, the PC file-serving applications are offloaded to a dedicated processor to improve performance. With no need for a separate PC server outside the AS/400, the customer has a single-server environment. The AS/400 provides the integrated security, integrity, and administration functions for the file server. For example, one of the supported file systems in the IFS is called QLANSrv, which is the file system the file server uses. Some simple commands can move data to and from the other file systems. In addition, the file server has access to all the devices on the AS/400.

A disadvantage of a separate PC file server is that it must have its own disk drives. If the data in this server is critical business data, the customer will no doubt want to take some precautions to protect that data. The AS/400 can automatically back up the data in case something should happen to the disk drives in the server, but even that may not be enough. Many customers want a high-availability disk system to protect the data and to ensure that the business is not disrupted if a disk fails. Disk mirroring and RAID disk technologies are available for PC servers. To address the issue of security, software packages exist that can be added to the server to provide various levels of security.

The problem with a separate PC file server is the duplication of resources. If the AS/400 already implements disk mirroring or RAID technology, it may make sense to use the disk devices in the AS/400. The same is true for security — it doesn’t make sense to purchase something the AS/400 already has. One obvious answer is to put the PC under the covers of the AS/400 and give it access to the AS/400 resources, and that is exactly what the IPCS does.

Using an IPCS in a remote AS/400 instead of having a separate PC server at that location can have additional benefits. Suppose someone at the remote location added a new business application to the PC server, and that application caused the total amount of disk space on the PC server to be exceeded. If this were a separate PC server, and there were no trained personnel at the remote location, someone would have to travel to the location, back up the disk drive, install a larger-capacity disk, and reload the back-up copy. If the business had hundreds of these remote locations, the upgrade costs would be enormous. But because the IPCS uses a portion of the AS/400 disk, someone from a central site can change the amount of disk space allocated to the IPCS.

The success of the IPCS demonstrated that separate application engines under the covers of an AS/400 could provide benefits to AS/400 customers who did not want to deal with separate PC servers. IBM decided to extend the concept of these application engines to other server operating systems, specifically Unix and Windows NT.

We first introduced the Unix application processor in early 1997 to satisfy the requirements of one large customer who needed to have both an AS/400 and a Unix server installed in many remote offices. (We later made the Unix application processor available to other AS/400 customers who also needed to run both Unix and AS/400 applications.) Putting a Unix server under the covers of an AS/400 allowed this customer to have only a single system in each office and still be able to run both AS/400 and Unix applications. The integrated Unix server is a card, similar to the IPCS. Unlike the IPCS, which uses an Intel processor, the Unix server uses a PowerPC processor. AIX, IBM’s version of Unix, is the operating system for this integrated server. I should note that the AIX integrated server also has its own local devices and shares some device drivers with the AS/400.

Windows NT running on an IPCS is another example of how you can integrate a full application server into the AS/400. The first implementation uses an Intel Pentium Pro processor. Initially, Microsoft Windows NT Server 4.0 functions as the operating system, but you can upgrade this to later versions of NT Server. IBM first delivered this Windows NT application processor to business partners and early adopters in 1997, with general availability to all AS/400 customers in early 1998.

Because any Intel-based NT Server application can run on this IPCS, IBM had to add certain local devices, including a keyboard, mouse, and display. Thus, unlike the original IPCS, this one has connectors for these local devices. In addition, there are provisions for attaching other PCI device adapters to this application server. Still other devices, such as disks, CD-ROM and LAN adapters, are shared with the AS/400. To accomplish this sharing, the NT application processor uses the AS/400 device drivers.