Job Prints While Spooling Option Ineffective With LPR

• Microsoft Windows NT operating system versions 3.5 and 3.51
• Microsoft Windows NT Server versions 3.5 and 3.51

SYMPTOMS

If you run Print Manager, choose either Create Printer or Printer Properties from the Printer menu, choose Details, and select Job Prints While Spooling for a printer that prints using LPR, the option has no effect when you print.

CAUSE

Enabling the Job Prints While Spooling option saves time by sending the first part of the print job to the print device as soon as the spooler receives it, rather than waiting for the entire job to finish spooling before sending it to the print device. Technically, this option tells the local print provider to despool print jobs to the print monitor (LPR in this case) before the local print provider has finished receiving the print job. If the print monitor immediately starts sending the print job to the print device, then this option saves time as described above.

Most print monitors send data immediately upon receiving it, but LPR cannot. Per LPR specification (RFC1179), the LPR print monitor and command line utility supplied with Windows NT, always send a control file with each data file. The control file includes a count of the number of bytes in the data file. As a result, LPR cannot send any part of the data file until it sends the control file, and it cannot send the control file until it has received the entire data file from the local print provider. This negates the effect of the Job Prints While Spooling option.

STATUS

Microsoft has confirmed this to be a problem in Windows NT versions 3.5 and 3.51. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.