8/3/2023 0 Comments Xz unzip fileWith two consecutive buffers, the pipe could keep downloading and extracting for a while in the background.īut without a buffer, the whole pipe would immediately slow down at once, and would rarely ever reach full speed again. Even if it didn't, without a buffer the whole pipe is sensitive to slowdowns.įor example, when flashing directly from the internet, I found that some USB devices occasionally did a flush or something, and that causes a periodic slowdown. I'm pretty sure that a simple '>' would do it one bit at a time. Some text editing programs can open XZ files and display the contents without unzipping them. What if you dont even use dd, just `wget. ![]() (and when you want to have the world's fastest img downloader, every second counts.)Īdditionally, in my script I go a couple steps further by loading the first 100MB of the img into cache first, and also it uses the buffer package to overcome I/O bottlenecks for maximum efficiency. It usually cut down on download time by around 3 seconds. In my tests, I found it gives a bit of a buffer. The cp command (which is very fast in my tests) uses just 128KB block size (see strace cp. xz filename.sql Uncompress file ( will be replaced by filename.sql ). Just for my interest, why are you using "bs=10M" for the dd command? XZ Compress a file ( filename.sql will be replaced by ). Now I just use "cp" - its simple to use and fast enough in practice (slightly faster than dd bs=1m) I gave up trying to calculate everything and produce an optimal C program! So, given that the disk read times are near zero for this case only, whats the best read/write block size to give dd for the optimal overlap between reads and writes? Finally, view your extracted files and select them as needed. The extraction should create files in the folder. You should see a displayed list of files indicating it was successful. įor example, I usually download the image to a memory disk, then uncompress it and copy it to the raw device. XZ file location, type ‘tar xJvf ’, and press the Return key. Given all the above variables, any simple benchmark results will be meaningless. ![]() A simple windows command line tool (no install, just unzip) Its hosted on codeplex tartool, complete with the source code. But once I downloaded the file again, then used peazip, it worked. But for example if I downloaded it and it failed with 7-zip, then unzipping the same file with peazip or xz didn’t work even though 7-zip didn’t seem to modify the file. tar.gz, or.tar.bz2 file 7-Zip will automatically start. The trick was to download the file again from the website every single time I tried to unzip it. Its incredibly complicated given: different read/download speeds, decompression speeds, indeterminate overlap between reads and writes, disk write speeds, variable asynchronous disk block prefetch ranges, "sync" time, verification time, etc etc Instead of using 7-Zip on the command line, you can use the file manager and click on a. Believe it or not, with enough optimization, it can be faster to download an img, extract it, and flash it to a SD card, than to flash a local, pre-extracted.
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