Thin Client Performance
Ever since Thin Clients were conceived the message has always been that unlike PC’s the CPU on the Thin Client is unimportant. The concept this comes from is that the Server is doing most of the work and therefore the horsepower needs to be there. The Thin Client in this case is merely animating the screen content and sending the keyboard and mouse data to the Server. What we have seen however is that there are many instances where the performance of the Thin Client does make a big difference to the end user experience even when using Terminal Server or Citrix.
Applications on the server which use multimedia in particular are impacted by low performance Thin Clients. In recent tests we carried out the lower spec Thin Clients were simply unable to keep up with the demands for sound and vision at the same time. Even PowerPoint was enough to show up problems. Embedded applications such as 5250 are particularly susceptible to poor CPU performance. The OS is also an important consideration here, on the more traditional Ethernet terminals the CPU is often low speed, however because they are running only machine code, they perform well. These days end users are looking to move from traditional Ethernet terminals to Thin Clients, they are faced with the choice of Linux, CE and XPe as a possible way to go. Linux by far is the most efficient OS for 5250, provided that the Thin Client has enough power to run it. Linux requires a minimum configuration before it starts to be efficient. The manufacturer of the image for the Thin Client can also make a difference, i.e. if the creator of the image is also the creator of the 5250 program the priority given to the 5250 can be tweaked. If the company who designs the image uses a third party such as Ericom, no such tweaking can be done. 5250 also suffers from problems caused by terminating the power before the 5250 session is closed.
10ZiG (formerly BOSaNOVA) is one of the very few companies who terminate the 5250 session before powering down the Thin Client. This is done with the RBT Series Thin Clients. The issue this addresses is that users who were used to Twinax Terminals, they could simply power off the device and the AS/400 would know the device was no longer communicating. With TCP/IP the AS/400 has a logical session with the device, so both devices are maintaining this conversation. If the user powers of the device without first closing the 5250 session, the AS/400 still thinks the device is in operation and will not release the session to the device next time it is powered on.