SvarDOS community forum

Hi, perhaps some of you did not already know this: As of 6th July 2022, the current license holder of CP/M and its derivates (DR-DOS) placed the software under a truly free license. Long ago, when Caldera DR-DOS was open source but no free software, Udo Kuhnt started a project called Enhanced DR-DOS. It includes enhancements to the DR-DOS Kernel source code from Caldera, supporting FAT-32 and a bunch of other stuff. This development is known under the name EDR-DOS. While Udo Kuhnt stopped developing EDR-DOS long ago, E. C .Masloch (aka ECM) continued to work on it in recent times. EDR-DOS being free software and getting some love recently, I created a SvarDOS package for the current version maintained by ECM. It can be downloaded from my Nextcloud, until it is either included in the SvarDOS package repository (if Mateusz is interested in), or I finally manage to put some proper Website in place. Instructions on how to switch to the EDR-DOS kernel and back to the default are provided in the package, along with a tool called DRSYS.COM, which is a modified SYS.COM from the FreeDOS kernel tree I compiled for use with the EDR-DOS kernel. https://nextcloud.iww.rwth-aachen.de/index.php/s/ZcDX9tFcDyTescs Perhaps someone is interested. I tested the kernel the last days. On my Pentium system, this works well. I think its always nice to have alternatives. Thanks to Mateusz for the excellent PKG tool. Bernd

Update: There seems to be some incompatibility between the SvarDOS command.com and the EDR kernel, leading to system freezes. I did not notice this until now because I use a different shell, 4DOS. So, be careful with combination of kernel and shell you are using. Confirmed to work: FreeDOS Kernel - SvarCOM EDR-DOS Kernel - EDR Command.com Both Kernels - 4DOS Further, I modified the README.TXT to make sure no-one overwrites his/her SvarDOS COMMAND.COM. Re-uploaded package as edrdos-20231116+1.svp.

Hello Bernd, Yes, I am very interested in this, and thank you for having looked this up. SvarDOS currently relies on the FreeDOS kernel, but it is not a design or ideological decision of any kind, I am very open to alternative kernels, as long as they are stable enough and reasonably compatible with MS-DOS. I see that your package contains both the kernel and command.com. Can those two work independently? That is - any chance to run the EDR command.com on FreeDOS kernel, or having the EDR kernel support SvarCOM? If so, then it would probably make more sense to have two separate packages, esp. since the SvarDOS package manager already knows how to handle a COMMAND.COM package. And then perhaps I should look into extending the pkg tool so it can install/switch also kernels. Did you test the EDR kernel extensively? Are there any obvious shortcomings or limitations when compared to the FreeDOS kernel? Is it superior in any way that you observed? (memory footprint maybe?) Mateusz P.S. You'r very welcome to push your work into the SvarDOS package repository, I'm very curious to see where this may lead

Hello Mateusz, the EDR command.com is currently locked to the EDR-DOS kernel. Sadly, SvarCOM and the EDR-DOS kernel seem to be somewhat incompatible. I first did not notice this, because when starting SvarCOM on top of 4DOS (my default shell) everything is fine. I will try to investigate this further. Regarding the EDR-DOR Kernel, let me quote ECM: "The EDR-DOS kernel, alike RxDOS and unlike FreeDOS, is written entirely in x86 assembly language. (The command.com shell utilises the C language in parts.) It fully supports FAT32 file systems and LBA int 13h disk access. Further, it supports FAT+ for file sizes up to 256 GiB minus 1 Byte on local FAT FS file systems. [...] Furthermore, the DR-DOS kernel is a highly compatible 8086 DOS beyond what is offered by FreeDOS. " On my Pentium, I did not notice such of a difference in performance or functionallity between both FreeDOS and EDR-DOS kernels. But on lower-end machines the EDR kernel may play out some benefits. I am only at the start of this voyage and open to suggestions how to improve the package. Before uploading to the repo, I will try to find out where the incompatibility between SvarCOM and the EDR-DOS kernel may come from. Bernd