Sept 30th, 2002 - The Miva Virtual Machine (AKA Miva Empresa with Virtual Machine 4.02) has some stability issues and bugs that can cause some serious problems. But they won't affect everyone.
There are bugs related to new features, which is naturally not that big a deal since nobody is using those features with their current stand-alone applications, and Miva Merchant doesn't use them. But there are also problems with existing, and very important language features that affect both stand-alone applications and Miva Merchant.
The biggest issue is related to the a strange and inconsistent limit on how many files you can call with MvDO. Our testing has shown that it is not a problem with the max files setting, and that the problem is also exacerbated by opening dbf files, or even just opening a single dbf file multiple times with different aliases. The end result is the MVM crashes producing an internal server error while trying to do the MvDO.
The problems seem to be most prominent on systems with lessor resources. So that for example on a limited resource ViaVerio FreeBSD Virtual Private server environment the problem was so pronounced that you couldn't run the setup, or upgrade program for Miva Merchant successfully, nor could you access the Domain Settings, or pack the data files in the admin interface, unless you remove all but 30 or so modules. The tests on the FreeBSD machine were limiting out at around 100 files called using MvDO whereas on a much more powerful test server running RedHat Linux over at Cybrhost.com the same tests could handle many thousands of files.
But it isn't all about resources because that same test ran fine on a windows XP workstation using the Miva Mia VM, but on that same workstation a test using the new glosub_array function had a nasty problem of spitting out trash from memory into the output, whereas that same code ran smoothly on the freeBSD machine.
Does this mean that you shouldn't use the MVM, or shouldn't use Miva Merchant 4.14? Not necessarily, it depends on your reasons for wanting to use the MVM or Miva Merchant 4.14, the system you will be running it on, what third party software you may or may not be using, and many other factors.
Our basic advise is that unless you have what you feel is an absolute need for Miva Merchant 4.14, like using a new payment or shipping module that is only supported in that version, that you seriously consider waiting for anew more stable release.