Uniprint: Working with Epson devices and Page Counting.

Question:

Can we use Epson printers in our Pharos system?

Information:

When asked of Epson if they produce any drivers that are designed to work within a client/server environment, their answer is "no".

The Background:

We in Pharos Technical Support get this type of question all the time, and we typically do not provide an answer that leaves a warm fuzzy. Before you ask "Why are they saying this?", here is some background.

Printer drivers often support what is called a "client-server" function: I can install a driver on a Windows print server, share it, and then all of my Windows clients can simply connect to my share, download a local instance of the driver files and settings, and print as much as they want to all day long. In this scenario, the print job normally leaves the client workstation as an EMF (enhanced metafile) blob containing all of the necessary bits (fonts, images, printer settings) it needs to the print server, normally via an RPC (remote procedure call) connection. At the print server, the EMF is converted into whatever PDL (page description language: PCL 5, PCL 5, PostScript, HP-GL/2, etc.) is used by the printer driver. This type of arrangement has been working well since Windows NT 3.51 was released. In Windows 2008 with Vista or Windows 7 clients, the EMF is often converted to the PDL at the client, leaving the server very little to do except route the job to the printer through the designated port (this happens when the "Client Side Rendering" box is checked on the Sharing tab).

Some printer drivers do not support this type of workflow. In the industry, they are called "host-based" printer drivers. Host-based drivers are exactly what they claim to be: a driver

that is installed on the computer creating the print file. In many cases, these drivers use a modified version of a common PDL, or they send data in their own, proprietary file format. Or, they utilize some type of communications path to the print device that does not work well in a client-server scenario. One thing is common for all host-based printer drivers: they use a lot of system resources when they're creating their file, and this is normally what makes them completely unsuitable in a client-server environment like Pharos Uniprint (can you image if one print request consumes 5% of your CPU and almost 20MB of memory what 5 or 6 simultaneous print requests at a server would do?).

In the end:

So how does this factor in to what our statement regarding plotter support is, then?

Our statement is simple and vague at the same time:

Provided the driver utilizes a supported PDL (see Which printer drivers are supported by Pharos Uniprint and Blueprint? for the latest list) and supports a client-server environment, it should work well within the Uniprint suite. Not exactly a cut-and-dried response.

Most plotter drivers, particularly those from Epson, are host-based drivers and must have a bidirectional communications path (either by connecting via USB/Firewire or via a direct TCP/IP path) to the print device in order to work, and because of the way a Uniprint package is installed (both in Windows and MacOS), bidirectional support is lost, so it won't work. In fact, if you look for a server-compatible driver on most wide-format plotter's manufacturer's websites, you will not find one.

While Uniprint supports most PDLs out there, we still must operate in the context of a client-server configuration. So contacting the manufacturer's support group is a good first step, because if they support client-server, we should be able to support it in Uniprint. This takes me to David Marcinkowski's first post regarding RIP (Raster Image Processor) software (Re: Can you restrict the release station to release one print at a time?) By its very design, most RIPs must be client-server oriented, so their drivers for Windows and MacOS work very well in Uniprint. RIP software usually standardizes paper sizes to the classic "ARCH" ISO sizes, making them very easy to integrate with the Uniprint Job Cost Method.

We trust that the background provided creates understanding towards what appears to be an indirect statement of support of plotters within Uniprint.