OK. See how write and read works.

$strace echo -n "abcd" > /dev/memory(/home/aravind/me write(1, "abcd", 4)                     = 1 write(1, "bcd", 3)                      = 1 write(1, "cd", 2)                       = 1 write(1, "d", 1)                        = 1

$ strace cat /dev/memory(/home/aravind/memory)

read(3, "d", 32768)                     = 1 write(1, "d", 1d)                        = 1

Please allocate space for more than 1 char, and also correct memory_write tmp=buf+count-1; -> tmp=buf+*f_ps-1; thanks, Daniel.