Talk:/dev/zero

Untitled 2005 topic
I've always wondered why there isn't a /dev/one, or some such, that when read produces a continuous stream of byte 0xFF.


 * You could create one. Just stick a NOT on the end of /dev/zero... right? --Ihope127 00:13, 12 July 2005 (UTC)

#! /bin/sh tr '\000' '\377' < /dev/zero

Paul Beardsell 03:30, 2 Sep 2004 (UTC)

Some Python code to demonstrate what /dev/zero gives you:

f=open('/dev/zero', 'r') print repr(f.read(4)) '\x00\x00\x00\x00'

The unix infinite loop
cp /dev/zero /dev/null


 * Only if you have a very braindead version of cp. It should copy the device file. Arbitrary username 20:05, 13 June 2006 (UTC)

Then try: cat /dev/zero > /dev/null /dev/zero 16:04, 13 September 2006 (UTC)

BSD-way od implementing shared memory
Mmap can be used to implement shared memory, it is true. But this shared memory need to have storage in file. Using mmap on /dev/zero is equivalent to use MAP_ANON flag. This mapping is anonymous, so can be shared only with children by inheritance. So maping of /dev/zero cannot be used to implement general shared memory.. -- Wieczyk —Preceding unsigned comment added by 81.190.193.233 (talk) 17:03, 15 September 2009 (UTC)

blocksize
Someone seems to believe that Unix ran only on 32-bit platforms. Actually all of the survivors got into 64-bits in the early/mid-1990s, so as usual, limitations should be specified with regard to the specific implementation. TEDickey (talk) 23:20, 11 September 2017 (UTC)