Download Figures From MrPLC.com

[BobB]

I noticed this morning that the entry page at MrPLC.com shows 4490 downloads for "CX-Programmer Ver.5 Introduction to Function Blocks Guide R121-E1-01". Can this be right? Heck of a lot of downloads for that manual if it is correct!!!

[Chris Elston]

That's one of the reasons we changed the downloads to ZIP now instead of PDF. I am in the process of converting PDF uploads to ZIP files. Apparently if the USER has a bad connection, especially 56K, they try to open the PDF in live mode direct from the site, instead of choosing download all PDF to your desktop. Or what I refer to it as a streammed PDF download, where if you open a PDF online, it launches the PDF viewer then shows you page one. When you scroll down, another download request is made and page two is downloaded to your browser and waits. So it keeps querying the server for more information. In the OLD days, when we only had about 10-30 people online at a time this wasn't a problem. Now-a-days we have 100+ online at a time and I see tons of open PDF requests. Basically, this is still a single server machine and can't really handle all those open PDF requests. The downloads section is very busy all the time. So in order to keep the server from lagging and crashing for now, because we need to upgrade it again to handle the load, I had to enforce this download rule. I would rather see the users download the whole file, then ask for it in little pieces at a time. I think FireFox does something fishy too but I can't prove it right yet. Firefox has a resume download and resume feature in FireFox seems to open a HTTP connection and doesn't close it. Hence one single user can have up to 1,000+ HTTP connection to the server feeding it a streammed PDF file that is 60MB in size. Generally it's the large PDFs that cause this problem. When that many HTTP connections are made the server freezes and shuts down. It gets slow, then the fail safe kicks in, boots everyone off the server, restarts all services, and resumes. (Gotta love Linux)....all automatically. In a nut shell, we are growing again, need to upgrade the server, but in the mean while I came up with this to force the entire 60MB file which was a PDF now ZIP file download. We have plenty of bandwitdh to give away, so download the entire file is only 1 HTTP connection and the server lives...If you notice another spike in a download, check to see if it's a large PDF, if it is, alert me and I will convert it. So to answer your question, yes and no the numbers are bogus. Mainly yes, but that is how many times the file was requested by the browser.