mTCP Ping
2013-04-26 Version
Michael Brutman (mbbrutman@gmail.com)


Introduction

  This is a DOS version of the 'Ping' utility commonly found on systems
  that support TCP/IP.  Ping allows you to do a basic check to see if
  a remote system is alive and responding to TCP/IP even if it is not
  accepting connections on specific ports.  Ping is also useful for
  measuring how far away (also known as the ping latency) of a remote
  system - lower ping times mean better performance.


Hardware requirements

  8088 processor or better
  56KB available RAM
  CGA, Monochrome (MDA), EGA or VGA display
  Supported Ethernet card, SLIP or PPP connection


Software requirements

  DOS 2.1 or newer
  Packet driver for your Ethernet adapter


Setup instructions

  Ping is built using the mTCP library.  The setup instructions for
  mTCP can be found in SETUP.TXT.


Using Ping

  Usage is like this:

    ping [options] <your.machinename.here>

  Options are:

    -help          Show a help message
    -count         Tell ping how many ping packets to send
    -size          Set the size of the test data in each packet

  By default ping will send four packets and each packet will have
  a 32 byte test message in them.  The total packet size will be
  60 bytes, including the TCP/IP headers.

  You can tell ping to send more packets or to send bigger packets.
  The test data portion of a packet can be up to 256 bytes in size.

  Ping sends one packet per second.

  Here is some sample output:

    E:\ping -count 5 -size 256 www.brutman.com

    Ping by M Brutman (mbbrutman@yahoo.com)
      Version: Sep 30 2009

    ICMP Packet payload is 256 bytes.

    Packet sequence number 0 received in 72.25 ms, ttl=49
    Packet sequence number 1 received in 70.55 ms, ttl=49
    Packet sequence number 2 received in 72.25 ms, ttl=49
    Packet sequence number 3 received in 73.10 ms, ttl=49
    Packet sequence number 4 received in 74.80 ms, ttl=49

    Packets sent: 5, Replies received: 5, Replies lost: 0
    Average time for a reply: 72.59 ms (not counting lost packets)



  You can press CTRL-C or CTRL-BREAK to stop.  If you ping a
  non-existent machine you will either get a DNS error message
  or an ARP failure.


Fun notes

  Normal timer resolution under DOS is limited to 55 milliseconds.  This is how
  fast the BIOS timer clicks, and it works out to about 18 times a second.

  Ping can measure time down to 0.85 milliseconds.  To do this it reprograms
  the hardware timer to generate interrupts faster, and then only passes the
  correct number of interrupts to the BIOS code.  This way BIOS keeps correct
  track of the time and everything else works as it should, while Ping can
  get 1 millisecond accuracy while it needs it.

  This technique is highly accurate - try it!


Support

  Have a comment or need help?  Please email me at mbbrutman@gmail.com.


Recent changes

  2012-04-29: Fix packet length problem
  2011-05-27: First open source release (GPL3)
  2010-06-21: Ported to Open Watcom
  2009-09-30: Higher resolution timing
  2009-09-25: Initial version


More information: http://www.brutman.com/mTCP

Created September 25th, 2009, Last updated April 26th, 2013
(C)opyright Michael B. Brutman, mbbrutman@gmail.com
