The Tiny PXE Server download package (pxesrv.zip) contains the executable, a range of Network Bootstrap Programs (iPXE, Grub4dos, PXELINUX, etc), sample menus for the included Network Bootstrap Programs and some other useful utilities. A full breakdown of the contents of the pxesrv.zip is included in this document.
The program author describes three main usages for Tiny PXE Server -
troubleshooting - boot a live system (WinPE, Linux, etc) for recovery purposes or data retrieval.
diskless boot - boot an operating system over a network on systems without storage media (e.g. a thin client).
Operating System Deployment - install an operating system on a client PC without the ability to boot to another media (e.g. install Windows XP on a netbook without a CD/DVD drive).
I would also add the following usage -
Digital Forensic Acquisitions - boot a forensic operating system (e.g. a WinPE based Windows Forensic Environment) and use it to image the client PC over a network. See here
Tiny PXE Server is freeware - please refer to the licence in the download package. This document is intended as an introduction to Tiny PXE Server (version 188.8.131.52 - dated 12/2/2017 (19:29)) - the content may also apply to other versions. Please note that there are multiple builds of older version of Tiny PXE Server and there is no clear way of differentiating between them. The program author has started adding a text file (version.txt) to the download package with version details.
Contents of version.txt from the Tiny PXE Server version used in this guide -
The following links contain a wealth of useful information, including advanced settings not covered in this document -