Check the CC and CFLAGS lines in the makefileIf your C library does not support the times(3) function, change the#define TIMES to#undef TIMES in speed.cIf it does, check the HZ value for the times(3) function.If your system does not define CLK_TCK it will be assumed tobe 100.0.If possible use gcc v 2.7.?Turn on the maximum optimising (normally '-O3 -fomit-frame-pointer' for gcc)In recent times, some system compilers give better performace.type 'make'run './destest' to check things are ok.run './rpw' to check the tty code for reading passwords works.run './speed' to see how fast those optimisations make the library run :-)run './des_opts' to determin the best compile time options.The output from des_opts should be put in the makefile options and des_enc.cshould be rebuilt.  For 64 bit computers, do not use the DES_PTR option.For the DEC Alpha, edit des.h and change DES_LONG to 'unsigned int'and then you can use the 'DES_PTR' option.The file options.txt has the options listed for best speed on quite afew systems.  Look and the options (UNROLL, PTR, RISC2 etc) and thenturn on the relevent option in the MakefileThere are some special Makefile targets that make life easier.make cc		- standard cc buildmake gcc	- standard gcc buildmake x86-elf	- x86 assembler (elf), linux-elf.make x86-out	- x86 assembler (a.out), FreeBSDmake x86-solaris- x86 assemblermake x86-bsdi	- x86 assembler (a.out with primative assembler).If at all possible use the assembler (for Windows NT/95, useasm/win32.obj to link with).  The x86 assembler is very very fast.A make install will by default installlibdes.a      in /usr/local/lib/libdes.ades           in /usr/local/bin/desdes_crypt.man in /usr/local/man/man3/des_crypt.3des.man       in /usr/local/man/man1/des.1des.h         in /usr/include/des.hdes(1) should be compatible with sunOS's but I have been unable totest it.These routines should compile on MSDOS, most 32bit and 64bit versionof Unix (BSD and SYSV) and VMS, without modification.The only problems should be #include files that are in the wrong places.These routines can be compiled under MSDOS.I have successfully encrypted files using des(1) under MSDOS and thendecrypted the files on a SparcStation.I have been able to compile and test the routines withMicrosoft C v 5.1 and Turbo C v 2.0.The code in this library is in no way optimised for the 16bitoperation of MSDOS.When building for glibc, ignore all of the above and just unpack intoglibc-1.??/des and then gmake as per normal.As a final note on performace.  Certain CPUs like sparcs and Alpha often givea %10 speed difference depending on the link order.  It is rather anoyingwhen one program reports 'x' DES encrypts a second and another reports'x*0.9' the speed.