Normally operating system simply maps binaries, executables and loadable libraries (.dylib, .so, .dll, etc.) into memory. The cost is approximately same whether

Normally operating system simply maps binaries, executables and loadable libraries (.dylib, .so, .dll, etc.) into memory. The cost is approximately same whether you do this once or 1000 times. The code is executed from the mapped area as-is. However, when a binary is compressed, this cannot work, because in the file the binary is represented as a compressed data. The only way you can work around is to allocate some memory, decompress the binary there, map the region as executable and run it from there. This results a non-shareable copy of the data for each running instance. A random link about this issue in practice: https://github.com/nushell/nushell/issues/4131 https://github.com/nushell/nushell/issues/4131