[TUHS] Abstractions

[Charles H. Sauer]

To add to the inventory below:
Dell SVR4 /bin is a symlink to /usr/bin
NEXTSTEP/486 3.3 /bin and /usr/bin are separate

On 2/23/2021 1:37 PM, Nelson H. F. Beebe wrote:
> The recent discussions on the TUHS list of whether /bin and /usr/bin
> are different, or symlinked, brought to mind the limited disk and tape
> sizes of the 1970s and 1980s.  Especially the lower-cost tape
> technologies had issues with correct recognition of an end-of-tape
> condition, making it hard to span a dump across tape volumes, and
> strongly suggesting that directory tree sizes be limited to what could
> fit on a single tape.
> 
> I made an experiment today across a broad range of operating systems
> (many with multiple versions in our test farm), and produced these two
> tables, where version numbers are included only if the O/S changed
> practices:
> 
> ------------------------------------------------------------------------
> Systems with /bin a symlink to /usr/bin (or both to yet another common
> directory) [42 major variants]:
> 
> 	ArchLinux		Kali			RedHat 8
> 	Arco			Kubuntu 19, 20		Q4OS
> 	Bitrig			Lite			ScientificLinux 7
> 	CentOS 7, 8		Lubuntu 19		Septor
> 	ClearLinux		Mabox			Solaris 10, 11
> 	Debian 10, 11		Magiea			Solydk
> 	Deepin			Manjaro			Sparky
> 	DilOS			Mint 20			Springdale
> 	Dyson			MXLinux 19		Ubuntu 19, 20, 21
> 	Fedora			Neptune			UCS
> 	Gnuinos			Netrunner		Ultimate
> 	Gobolinux		Oracle Linux		Unleashed
> 	Hefftor			Parrot 4.7		Void
> 	IRIX			PureOS			Xubuntu 19, 20
> 
> ------------------------------------------------------------------------
> Systems with separate /bin and /usr/bin [60 major variants]:
> 
> 	Alpine			Hipster			OS108
> 	AltLinux		KaOS			Ovios
> 	Antix			KFreeBSD		PacBSD
> 	Bitrig			Kubuntu 18		Parrot 4.5
> 	Bodhi			LibertyBSD		PCBSD
> 	CentOS 5, 6		LMDE			PCLinuxOS
> 	ClonOS			Lubuntu 17		Peppermint
> 	Debian 7--10		LXLE			Salix
> 	DesktopBSD		macOS			ScientificLinux 6
> 	Devuan			MidnightBSD		SlackEX
> 	DragonFlyBSD		Mint 18--20		Slackware
> 	ElementaryOS		MirBSD			Solus
> 	FreeBSD 9--13		MXLinux 17, 18		T2
> 	FuryBSD			NetBSD 6-1010		Trident
> 	Gecko			NomadBSD		Trisquel
> 	Gentoo			OmniOS			TrueOS
> 	GhostBSD		OmniTribblix		Ubuntu 14--18
> 	GNU/Hurd		OpenBSD			Xubuntu 18
> 	HardenedBSD		OpenMandriva		Zenwalk
> 	Helium			openSUSE		Zorinos
> 	
> ------------------------------------------------------------------------
> 
> Some names appear in both tables, indicating a transition from
> separate directories to symlinked directories in more recent O/S
> releases.
> 
> Many of these system names are spelled in mixed lettercase, and if
> I've botched some of them, I extend my apologies to their authors.
> 
> Some of those systems run on multiple CPU architectures, and our test
> farm exploits that; however, I found no instance of the CPU type
> changing the separation or symbolic linking of /bin and /usr/bin.
> 
> -------------------------------------------------------------------------------
> - Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
> - University of Utah                    FAX: +1 801 581 4148                  -
> - Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
> - 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
> - Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
> -------------------------------------------------------------------------------
> 

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