Definition
All hardware and software components involved in printing are combined in the print architecture.
Depending on the order of these individual components, an architecture that fulfills different purposes and requires a specific print method, such as those listed below, is produced:
· Local printing
· Remote printing (network)
· Frontend Printing (SAP GUI for Windows)
Structure
The figure below shows the individual components of the print architecture that are required to print from the SAP System:
The individual components interact as follows:
1. After the user triggers the print process, the print requests are sent to the spool server, which contains the dialog and spool work processes required for the processing.
2. A dialog work process (D-WP) of the spool server forwards the spool data to the spool database for temporary storage.
3. When the data is explicitly sent to an output device, an output request is generated from the spool request. This is forwarded to the spool work process (S-WP).
4. The spool work process formats the output request data.
This converts an internal data stream of the SAP Systems to a data stream that the output device understands.
5. After formatting, the spool work process forwards the print request to the host spool system (operating system spooler). The host spool system has the following tasks:
- Wait queue management
- Transferring the data to the output device
Depending on the situation of the host spool system, one of the following print types is used:
- local: The print requests are forwarded to the printer through a local network. The host spool system and the spool work process are on the same host.
It is irrelevant whether the output device is directly connected to the server, or whether it is defined using a remote print server.
- remote: The print requests are forwarded from the spool work process to the printer through a remote network. The host spool system is on a different host to the spool work process. This remote host is called the target host.
1. Local Printing (Access Methods C and L)
Use
Use local printing if the host spool system (operating system spooler) and the spool work process of the SAP System are on the same host.
The print architecture has characteristics typical of local printing, explained below.
Local printing is the fastest and most reliable form of printing from the point of view of SAP Systems. You can use local printing for the following operating systems:
● all Windows platforms that SAP supports for application servers
● UNIX
All other operating systems use remote printing.
Prerequisites
Architecture Prerequisites
● The system prints locally if the host spool system (operating system spooler) and the spool work process of the SAP System are on the same host.
● It is irrelevant whether the printer is directly connected to the PC or whether it is a shared network printer.
● The printer must be defined at operating system level of the spool server.
SAP System Prerequisites
To be able to address an output device from the SAP System in which you are working, you must define the output device in this SAP System. You do this using a device definition.
When you are configuring the output device in a device definition, you specify how the printer is connected to the SAP System using the access method. The access method specifies whether you are using local or remote printing. The access method is identified by a letter and informs the system which architecture is in use and which operating system you are using. In this way, the system knows the way in which data is to be transferred.
The system uses the following access methods for local printing, depending on the operating system that you are using:
- Access method C: supported on all Windows plattforms that SAP supports for application servers; iServer eSeries
- Access method L: UNIX
The figure below illustrates how your print architecture must look so that it can be used for local printing:
Activities
● With local printing, the spool work process of the SAP Systems transfers the output stream, formatted for the printer, to the host spool system (operating system spooler) on the same host. The system uses the access method (C or L) that you have specified in the device definition.
The data does not need to be transferred over a network connection to reach the host spool system, which makes the connection fast and reliable.
● The data stream is printed using a local or remotely connected printer.
Remote Printing (Access Methods S and U)
Use
Use remote printing if you are printing over a network; that is, when the host spool system (operating system spooler) and the spool work process of the SAP System are on different hosts.
The print architecture has characteristics typical of remote printing, explained below.
Prerequisites
Architecture Prerequisites
● The system prints remotely if the host spool system (operating system spooler) and the spool server of the SAP System (application server with a spool work process) are on different hosts.
● There must be a network to transfer the data to the print server.
● Fixed IP addresses are required (unlike frontend printing).
● It is irrelevant whether the printer is connected locally or remotely to the application server.
● Remote printing requires reliable communication partners so that timeouts do not occur.
SAP System Prerequisites
To be able to address an output device from the SAP System in which you are working, you must define the output device in this SAP System. You do this using a device definition.
When you are configuring the output device in a device definition, you specify how the printer is connected to the SAP System using the access method. The access method specifies, for example, whether you are using local or remote printing. The access method is identified by a letter and informs the system which architecture is in use and which operating system you are using. In this way, the system knows the way in which data is to be transferred.
The system uses the following access methods for remote printing, depending on the operating system that you are using:
- Access Method U: UNIX systems; Microsoft Windows system (using a TCP/IP Print Server and SAPSprint)
- Access Method S: Microsoft Windows systems (using SAPSprint)
The figure below illustrates how the print architecture must look for remote printing:
Activities
With remote printing, the SAP spool work process sends the formatted data stream to the output device over a network connection.
The options for the data transfer to the output device are listed below:
● Transfer to a network printer
Network printers simulate their own host spool system. They can be directly connected to the network with a network card and receive SAP output data.
Access method U
● Transfer using a UNIX destination host
The host spool system is on a host that uses UNIX as its operating system. The data is forwarded to the Line Printer Daemon (lpd).
Access method U
● Transfer using a Microsoft Windows PC as the destination host
The host spool system is on a host that uses Microsoft Windows as its operating system. Depending on the access method, you can use SAPSprint from SAP or, for Microsoft Windows XP, the TCP/IP Print Server of Microsoft Windows XP. SAPSprint and TCP/IP Print Server accept the data stream and forward it to the host spool system.
Access Methods:
- S(proprietary SAP protocol) for use with SAPSprint.
- U (UNIX Berkeley protocol) for use with the TCP/IP Print Server of Microsoft Windows XP and with SAPSprint.
While data is simply forwarded with the access method U, the access method S has the following attributes:
○ Encrypted transfer, for example for HR data
○ Compressed transfer.
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