Since Newt 3.0, it's been possible to save packages directly on the Newton. For this you need the NewtPack plug-in which is provided with the standard release.
The NewtPack included with Newt should work on ALL Newtons. For older/original, pre-1.3 ROMs, non-upgraded OMP (Original MessagePads), NewtPack must use a "small save method" which limits the size of final packages. You should still be able to create modest-sized (~30-40K) packages. When NewtPack begins to save, the version/configuration appears -- NewtPack appends "+S" to the version number if it is using this "small" method.
NewtPack is relatively slow on 1.x; it is quite fast on NOS 2.x. However, since you can build and test your applications in Newt, you do not need to create a package until toward the end of your development process. The 2.x version of NewtPack is faster and more compact. There is also a version of NewtPack available to registered users that contains some native (RISC) code -- it is currently ~20% faster than the regular 1.x version, and somewhat larger.
If you used the older RUNewt mechanism, see RUNewt.
When you install NewtPack, it is an "autopart" that appears in Extensions for NOS 2.0 (but does not appear in Extras for 1.x). When Newt starts up, it finds the NewtPack plug-in, and automatically uses it to save your application, either via the Save button or :saveApp. As your package saves, NewtPack displays the most recent slot at bottom left, and current package size.
Unless you provide a "sizeHint", NewtPack does not display a progress gauge (on 2.0, it displays a "barber pole" along with a Stop button). You will hear a "funbeep" if NewtPack is successful and the progress box will automatically disappear; or, you will hear an error beep, see a message (for 1.x, a close box should appear on the progress box).
If there is an existing package with the same "appSymbol", e.g., myApp:Newt, Newt asks you to confirm removing the old package before proceeding. If an error occurs during saving, you might try again after a fresh restart, in case a heap problem was reported; otherwise, if you're creating an autopart or using an installScript, look at the examples & docs again, then send me email...
Packages generated with the generic NewtPack will work on any Newton. NewtPack 3.4-2 (and Newt 3.4-2) generates packages that are somewhat smaller and will install only on NOS 2.x systems.
If the package successfully saved and installed, it should be indistinguishable from an NTK-created package, and you should be able to use utilities that archive packages and manipulate Extras, e.g., NewtCase, ScrollEx, etc. For 1.x, you may wish to obtain one of these, or at least a utility that will allow you to scroll the "Remove Software" list -- newer 1.x system updates from Apple have a utility called "Package Mover" that allows the "Prefs:Memory:Remove Software" list to scroll. Let me know which work best for you (or don't work) so that I can pass along this info.
For 1.x, in addition to beaming any NTK or Newt package to another Newton via a utility like BeamPkg or ScrollEx, you can backup the package to your Mac or PC with Newton Connection Kit. Once there, you can extract the package from the NCK backup file with an Extract Package utility (and then copy to floppy, upload somewhere or attach to email).
For 2.x, ExtractPackage does not work on backups created by NBU (Newton Backup Utility) -- PackageBuddy, X-Port, Newton Package Uploader can be used to upload selected packages to a Mac or Windows desktop. (There is an earlier, less supported tool (named "Toss") that may work with a terminal emulator on other systems). NewtonLink can be used with Sloup to upload packages for Unix systems.
If you plan to distribute to others, I'd be glad to review designs and source and beta-test, as time permits. Please include the following acknowledgment in your "readme" (text file or online help):
This application created with the Newt Development Environment (Newt 3.4). For further information,
browse: http://communicrossings.com/html/newton/index.htm
Also, if you let me know the application location/URL, I can add your Newt-generated package to my list of applications and books.
There is no royalty for distributing your packages.