Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
DNIX
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
=== Features that were never added === When DNIX development at ISC effectively ceased in 1997, a number of planned OS features were left on the table: * [[Shared object]]s β There were two dynamically loaded libraries in existence, an encryptor for DNET and the GUI's imaging library, but the facility was never generalized. ISC's machines were characterized by a general lack of [[virtual address]] space, so extensive use of memory-mapped entities would not have been possible. * [[Lightweight process]]es β The [[Kernel (operating system)|kernel]] already had multiple threads that shared a single MMU context, extending this to user processes should have been straightforward. The [[API]] implications would have been the most difficult part of this. * [[Access-control list]]s (ACL) β Trivial to implement using an ACL handler mounted over the stock file system. * Multiple swap partitions β DNIX already used free space on the selected volume for swapping, it would have been easy to give it a list of volumes to try in turn, potentially with associated space limits to keep it from consuming all free space on a volume before moving on to the next one. * Remote kernel debugging via [[gdb]] β All the pieces were there to do it either through the customary serial port or over Ethernet using the kernel's embedded X.25 link software, but they were never assembled. * [[68030]] support β ISC's prototypes were never completed. Two processor piggyback plug-in cards were built, but were never used as more than faster 68020's. They were not reliable, nor were they as fast as they could have been due to having to fit into a 68020 socket. The fast context switching ISC MMU would be left disabled (and left out altogether in proposed production units), and the embedded one of the 68030 was to have been used instead, using a derivative of the DS90-20's MMU code. While the ISC MMU was very efficient and supported instant switching among 32 resident processes, it was very limited in addressability. The 68030 MMU would have allowed for much more than 8 MB of virtual space in a process, which was the limit of the ISC MMU. Though this MMU would be slower, the overall faster speed of the 68030 should have more than made up for it, so that a 68030 machine was expected to be in all ways faster, and support much larger processes.
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)