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Hello, Laurence. |
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On Tue, Jan 19, 2021 at 17:09:03 +0000, Laurence Perkins wrote: |
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> On Sun, 2021-01-17 at 05:17 +0000, Thomas Mueller wrote: |
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> > On Sat, 16 Jan 2021 12:01:48 +0000, Alan Mackenzie wrote: |
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> > > I don't know what I'll be doing, long term. For the moment, I'll |
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> > > be hanging onto the working kernel I've got, old though it may be |
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> > > (4.19.97). It might be possible (I'm not sure) to hook up a user |
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> > > space program to the keys <shift>-<PageUp/Down> which would take |
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> > > care of the scrolling. This would obviously not work with early |
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> > > kernel messages, but would be better than nothing. I had a look at |
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> > > the GNU screen source code yesterday to see how it managed such |
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> > > things, but it is very sparsely commented, and thus hard work to |
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> > > understand. Maybe I should just cut my losses, and convert to |
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> > > using one of the BSDs. |
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> > 2000 posts per day on Linux kernel list would be more than |
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> > unmanageable for me! I wouldn't say "almost"! |
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> > Is Linus Torvalds' removal of console scrolling the reason why Scroll |
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> > Lock does not work on the console with System Rescue CD or USB, while |
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> > with FreeBSD and NetBSD, I can press Scroll Lock and scroll back? |
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> > I like that ability but don't think Linus Torvalds is listening or |
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> > reading this. |
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> > Further, with System Rescue console, the lines/text go only partway |
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> > down. |
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> > Using screen, now at v4.8, means having to remember a lot of key |
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> > functions, you need a separate reference screen to look them up. |
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> > There is also tmux, which is part of the base system in NetBSD but |
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> > not FreeBSD. |
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> > If Linus cared about his users, he could make the kernel headers more |
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> > user-friendly, installing kernel headers should not be any more |
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> > complicated than copying or downloading. |
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> > Console scrolling is especially useful with an OS or distro that is |
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> > built from the ground up, like Gentoo, Void or Arch, as opposed to |
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> > being installed all at once. |
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> > If more Linux users would go to and try NetBSD or FreeBSD, those OSes |
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> > would have more users, more ideas, more ability to improve. |
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> > You can even cross-compile NetBSD from Linux. You'd need NetBSD |
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> > source tree, but don't have to do anything special to install kernel |
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> > headers. |
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> > Tom |
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> You're getting this second-hand since it was my brother who actually |
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> looked into it, so pardon anything I misremember, but the big problem |
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> is that adding unicode support to vgacon would need a near total |
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> rewrite, and nobody wants to do that since it's a terrible hackjob to |
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> start with. |
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> kmscon is slated to be the replacement. You might want to see if that |
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> can do what you need. |
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I looked kmscon up on Wikipedia, and apparently development ceased |
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several years ago. |
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What I have in mind now is writing a Linux driver, a small piece of code |
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which would piggy-back on the existing virtual terminal drivers, and |
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simply pass everything through to and from the main driver, filtering out |
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things relevant to scrolling, and processing these in my new driver. |
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I've spent the last few evenings reading up on drivers, and reading the |
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relevant source code from 4.19.97. I can understand the kernel |
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maintainers not being enthusiastic about the existing code. But that |
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dates from, I believe, the 1990s, when RAM was measured in megabytes, and |
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processor speeds in megahertz. Optimisation for speed and store usage |
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just isn't important any more. |
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> LMP |
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-- |
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Alan Mackenzie (Nuremberg, Germany). |