How to save number to file at bin type ?

Hello php-general, First, I must say sorry for my english poor. I have an array('255','1234','121344343'), I want save it at file: file size = 9 byte ########################## 00 FF 00 04 D2 07 3B 91 57 ^^^^^ ^^^^^^^^ ^^^^^^^^^^^ 255 1234 121344343 ########################## not file size = 16 byte ################################################# 32 35 35 31 32 33 34 31 32 31 33 34 34 33 34 33 2 5 5 1 2 3 4 1 2 1 3 4 4 3 4 3 ################################################# btw: dec(255) = hex(0xFF), dec(1234) = hex(0x04D2), dec(121344343) = hex(0x073B9157) asc("2") = hex(0x32), asc("5") = hex(0x35), So, I mean "I want retrench file size, Then file can be transfer fast", And how to output it to user browser ?? -- Best regards, php