Almost every time I've had to change the print processor for a printer, it's because it's set to something other than WINPRINT/RAW. Granted, fax software sometimes makes use of other print processors, but most of the time it seems as though the WINPRINT/RAW processor is the best way to go. Can anyone shed some light on the history and need for different print processors? For instance, when different processors are needed and what types of symptoms can be seen if the wrong processor is being used?
Way back at the beginning of Windows, Windows printing was not considered reliable. The standard to which it was being compared was NetWare (this was the 1990's after all), which at the time had a good reputation for reliability. Because of this printer manufacturers created their own Print Processors under the impression that:
HP was prominent in this, and in fact still ships a print-processor with its drivers. Though in recent years their 'enterprise' product line has seen this less often, where their consumer product line tends to rely on it more. This has the side-effect (likely intentional) that their consumer product is a poor team player on centralized print-servers.
The Windows print-processor has gotten a lot better over the years. Even so, there are still some instances where a custom processor is needed.
At my old job at a large University, where we had something like 1700 computer-lab seats and printed about 2 million pages an academic quarter, we needed a custom processor for our print-auditing solution. As I understand it, it just acted as a shim between the spooler and the actual RAW provider that allowed for advanced features like tracking quotas and handling charge-back.
The above are for third party print providers that commonly come along with the driver install. Windows has its own providers, and I've rarely seen things set to anything other than "RAW".