My problem is that I don't understand how putting the apt cache in RAM is beneficial if what you're trying to do is avoid flash writes. If you're updating the cache, then you're also intending to install or upgrade software, which will write to flash. If it's in RAM and not persisted, forcing you to do an update each time you do an install or upgrade, how does this prevent writing to flash?
So, either I'm not understanding the intent, or I'm not understanding how apt works. If instead it's best practice to always update before installing, then why not have apt-get install just update the cache each time? All I see is no benefit but the potential for error (e.g., not getting the version of the package you thought you were getting, or in the best case, confusing errors due to conflicts). I don't see how putting the cache in RAM helps anyone, novice or expert. Now, if the intent is just to speed up accesses, rather than reduce flash writes, then loading the cache at boot from a store on disk, and accessing the cache in ram, makes sense. However, it seems that in this case, apt-get update should update both the cache and the on-disk store. In all this, I'm questioning the wisdom of the apt authors, not you or Robert or anyone else on this list. > On Oct 19, 2015, at 15:53 , William Hermans <yyrk...@gmail.com> wrote: > > I'm not attacking you, William, I'm asking for clarification. It doesn't make > any sense to me that apt-get update wouldn't write its results to disk. > > You don't need to apt-get update all the time, if it writes its results to > disk. But if it doesn't, and you forget to next time you apt-get install, you > run the risk of downgrading something you have installed (or otherwise > corrupting it), don't you? > > Not attacking you either Rick, but here is the point. The official images > come with this enabled. So whether you, I, or anyone else cares, it's already > in there. The apt sources cache is either completely in RAM, with a default > cache set at build time, or it is a minimal gzipped archive. Technically, no > you do not *have* to run apt-get update _every_single_time_ you go to use > APT, but generally it is a good idea. All it takes is an update in one repo > or another( depending ), and apt-get install, apt-get upgrade, etc will fail, > barfing out some message similar to E: could not locate x.y.z. > > Either way, the blog was meant for people who are new to Beaglebone, or Linux > development in general. If you're good with Debian(Linux), you probably do > not need my guides. > > Passed that, many people are worried about writing to flash too much, and I'm > one of them. I've been using an A5A for gaining on 3 years now, with no flash > problems, and that includes the Sony class 10 SDHC card that we bought for it > back then. As it is, I make enough mistakes of writing to flash, > accidentally, to worry about all the compiling, apt-get installing, etc. This > is also why one of my first blog posts was on how to setup NFS shares, and > NFS root for the Beaglebone. Not to mention I compile often, and a lot. > Granted, compiling over an NFS share *is* slower, but I can live with that. > But it's also why I have a cross system for the larger projects, or is why I > wrote another blog on how to setup a USB rootfs . . . > > I was also a bit "quick" this morning . . . which is how I normally am for > the first few hours after waking up. Still, if I write something in my blog > posts, and you do not get it. Don't worry so much about it. It was probably > not meant for you, or other advanced users. It was meant to keep people, who > are new out of "trouble", with minimal explanation required from me. > > On Mon, Oct 19, 2015 at 2:13 PM, Robert Nelson <robertcnel...@gmail.com> > wrote: > On Mon, Oct 19, 2015 at 4:10 PM, Rick Mann <rm...@latencyzero.com> wrote: > > I'm not attacking you, William, I'm asking for clarification. It doesn't > > make any sense to me that apt-get update wouldn't write its results to disk. > > > > You don't need to apt-get update all the time, if it writes its results to > > disk. But if it doesn't, and you forget to next time you apt-get install, > > you run the risk of downgrading something you have installed (or otherwise > > corrupting it), don't you? > > It's really hard to down-grade in debian, and any cache corruption > should stop dpkg from installing a *.deb package.. > > Regards, > > -- > Robert Nelson > https://rcn-ee.com/ > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- Rick Mann rm...@latencyzero.com -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
