Dear All, I am running into a slightly odd issue when attempting to produce a png/pdf file in R under centos. The version of Centos is 5.6 with an old version of R 2.12.0 (2010-10-15). My script is roughly: mydata <- read.csv(myfile) png(outfile) plot(0,0,type='n',ylim=c(-500,500),xlim=c(0,700),xlab=... lines(mydata$x,mydata$y) dev.off() It produces a plot with the correct limits and labels but the lines command does not seem to always work (I have checked that the data fall within the defined limits!). No error message is reported. The data sets are reasonable large (~6.5 million lines) but not large enough to cause an issue? It runs fine on my windows machine albeit with the latest R build. If I loop over the data set plotting chunks at a time it works just fine. n <- floor(nrow(mydata)/1000000) for(i in 0:n){ lines(mydata[max((i*1000000),1) : min(((i+1)*1000000),nrow(mydata)),]) } I have googled and cant find anything helpful. Is it an issue with R, my R installation, Centos etc Thanks in advance, Roger