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Comment: Re:If only history (Score 1) 326

by m.dillon (#48398479) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

You obviously have not had to deal with customer/user complaints about filesystem corruption. Because if you had, you'd rapidly come to the conclusion that the manpower required to service all of those complaints, let alone track down the cause (which is virtually impossible if TRIM is enabled), not to mention the bad rep that you get whether it is your fault or not, is simply not worth it.

-Matt

Comment: Re:Easier solution (Score 1) 326

by m.dillon (#48398441) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

Complete nonsense. You seem to think that TRIM is some sort of magical command that makes SSDs work better. Spend a little more time on understanding the reality and your opinion will change.

Overprovisioning works extremely well. So well that there is really no reason to use TRIM, and plenty of reasons to avoid using it due to the many reasons stated by myself and a few others here.

Overprovisioning and TRIM do not have linear relationships. You don't get double the value by using both, or even double the value by, say, doubling the amount you overprovsion, or doubling the amount of free space the SSD thinks it has due to using TRIM. Beyond a certain point, overprovisioning and TRIMmed space will have only a minimal effect on actual wear because, as I've said already, a good SSD will do both static AND dynamic wear leveling. Dynamic wear leveling alone using TRIMmed or overprovisioned space, no matter how much space is available, only delays the inevitable need to relocate static blocks.

You can reduce the copying the SSD has to do, but beyond a certain point the amount of copying that remains will be so far under the radar compared to nominal filesystem operation (normal writes to files, etc), that it just won't have any more of an impact.

The non-deterministic nature of TRIM (depending heavily on how full your filesystem is and how fragmented it is), not to mention firmware bugs, filesystem bugs, the impossibility of diagnosing and tracking down corruption when it occurs, problems with feeding TRIMs through block managers which use large-block CRCs, and many other issues wind up creating huge complexities that increases your chance of hitting a bug somewhere that blows you up... it's just not a good trade-off. I will take the *highly* deterministic and generally bullet-proof overprovisioning method over TRIM any day of the week.

The only time I advocate using TRIM is when someone wants to wipe and repartition a SSD from scratch. That's it. I don't even advocate it for cleaning up the swap partition on reboot because then you can't recover crash dumps (and you might already be paging after that point so...). Though I suppose one could add some logic to TRIM the swap partition if no crash dump is present. That's about as far as I would go, though.

-Matt

Comment: Re:Why? (Score 1, Insightful) 326

by m.dillon (#48398181) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

I can't agree with your reasoning. The many computer companies that have lived and died over the years have primarily died because they were producing hardware that could not keep pace with developments in the industry.

Commodore .. which I was a developer for the Amiga (and a machine language programmer in my PET days), commodore died because AmigaOS was 100% dependent on Motorola and Motorola couldn't keep up with Intel, period.

NeXT died for the same reason. NeXT couldn't keep up with Intel and by the time Jobs caved in and went with his dual-architecture 68K/Intel binary format, it was too late. Also, depending on display-postscript for EVERYTHING was a huge mistake for NeXT and having 15+ year old OS tools for a weird Mach/BSD core that they never really updated messed them up too. I was a developer for the NeXT too.

In modern times, everyone runs on similarly powerful hardware and generally can stay up-to-date on the hardware front. OS makers die from a lack of apps or a lack of ease-of-use. Apple certainly does not suffer from either.

Linux and the BSDs are entirely dependent on a relatively common library of ~20,0000 to 30,000 or so (substantial) open source apps in order to stay relevant, but all suffer from the lack of a cohesive GUI that is powerful and easy to use. KDE, Gnome, the many other little window managers available... none hold a candle to either Apple or Windows. Unfortunately. At least as a consumer machine.

I have no problem running linux or a BSD as my workstation, as long as I am only doing programming or browsing. But if I want to play a *real* game or run *real* photo or video software (not something stupid like gimp which is virtually unusable)... then I have to shift my chair over to my Windows box or my refurbished Mac laptop. For that matter, if I want brainless printing which just works, I have to run it through my Windows box because CUPS is an over-engineered piece of crap that only works well on Macs... certainly not on linux or any of the BSDs.

-Matt

Comment: Re:Easier solution (Score 1) 326

by m.dillon (#48398073) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

That is definitely incorrect. TRIM issuance is a filesystem-level operation or a disk partitioning level operation, not an OS-level operation. Due to ordering constraints, the OS cannot safely manage TRIM in the manner you suggest. A filesystem can, but honestly I don't know any filesystems which use TRIM that way. Smart SSD firmware can also delay TRIM in that matter but I don't know any that actually do. The filesystem will either issue the TRIM semi-synchronously or it will issue the TRIM as part of a batch cleanup. If it issues it at all. There is a great deal of complexity involved, because filesystems will often gang small block operations into larger blocks and you can't use TRIM on small blocks if you do that and still hope to have your CRC checks work deterministically on the larger block.

Also, remember that for SATA/AHCI (not SAS), the NCQ stuff is a pretty bad hack based on the command id and the original TRIM could not be issued without waiting for all other I/O to complete, then issuing it synchronously, then starting up the I/O again. For small erase sizes, writing zeros would be much, much faster if only the SSD spec specifically stated that writing zeros would have a TRIM effect. But it doesn't. Also, writing zeros is deterministic (which is good for finding bugs). TRIM is non-deterministic, which makes finding bugs almost impossible.

So, for many reasons, TRIM is about the worst implementation it is possible to have for a SSD. It's only real use is to completely wipe (repartition / blow-away) an SSDs entire storage. Other use cases just don't work as well as you might think and would be better served actually pushing zeros and specing the SSD to detect the zeros and TRIM the block, and if not to ensure that the sector still reads back as all zeros so as not to blow up large-block CRCs and other sanity checks.

-Matt

Comment: Easier solution (Score 4, Interesting) 326

by m.dillon (#48397343) Attached to: Apple Disables Trim Support On 3rd Party SSDs In OS X

It isn't really true that SSD performance goes down by a whole lot if TRIM is not enabled. SSD performance and firmware has undergone radical improvements every year and people have come to the mistaken belief that enabling TRIM is responsible for most of the performance and wear leveling improvements.

TRIM has numerous problems, not the least of which being drives and/or filesystems which do not implement it properly. Because its use and effects can be seriously non-deterministic (even in a proper implementation), any bug in the drive firmware OR the filesystem in the use of TRIM can create serious corruption issues down the line when the drive actually decides to blow away some of the trimmed sectors. The TRIM command was badly conceived from the get-go.

The easiest and safest solution to getting 95% of the benefit of TRIM without actually using TRIM is to simply partition a factory fresh drive to leave a bit of unused space at the end... say another 5-10%. As long as it isn't written to, the drive will use that space as part of its dynamic wear leveling mechanic. As long as the drive also does static wear leveling (which nearly all will do these days), you wind up with nearly all the benefit of TRIM without having to actually use TRIM. TRIM was more important in the days where static wear leveling was not well implemented (or implemented at all). It is less useful these days.

-Matt

Comment: Anti-Spam Measure? (Score 3, Insightful) 245

by ewhac (#48365367) Attached to: ISPs Removing Their Customers' Email Encryption
Didn't this very topic come up a few days ago? I recall the general consensus being that it's an anti-spam measure, and (is supposed to) only happen when connecting on port 25 to a non-local machine (port 25 is supposed to be for server-server communication only). Normal clients are supposed to be able to avoid the issue by changing your MUA to submit mail on port 465 (smtps) or 587 (smtp). I suspect people running their own SMTP servers will probably need to negotiate with their ISPs, or relay their mail through their ISP's SMTP server as a smarthost.

Comment: Re:Why should I care? (Score 1) 122

by m.dillon (#48337803) Attached to: New NXP SoC Gives Android Its Apple Pay

My physical credit card (normal mag stripe) is compromised at least once a year and sometimes more often. I might not be liable for the fraud, but it is VERY inconvenient when it happens, the card gets locked out, plus it also causes my bank to start verifying more of the transactions which is just as inconvenient if I don't answer the text message quick enough and the card gets blocked for no reason.

It got so bad that around 2 years ago I got a second credit card so I could file it with trusted sites like Amazon and with charities that I donate to regularly and not have to give them all new card numbers every time my over-the-counter card got compromised. That's how bad it has been.

Chip-and-pin is less convenient than ApplePay. Tap-and-pay cards are nominally the same convenience as ApplePay but still have physical security issues. Mag stripe is clearly going to die soon... the data breaches are occurring so often now that not fixing it is no longer an option for merchants. They will have to go to NFC whether they like it or not.

I use ApplePay wherever I can now.

-Matt

Comment: NFC alone isn't enough (Score 2, Informative) 122

by m.dillon (#48337757) Attached to: New NXP SoC Gives Android Its Apple Pay

You need NFC (which many Android devices have had for years)... but you also need an actual secure chip (not a software emulation or intermediary), and the ability to initiate payment without having to turn on the phone or type in a security code (i.e. a fingerprint reader), and you have to be able to do it with the phone locked and turned off (meaning you need low power hardware to detect the NFC and wake the phone up). And then you need the OS integration to make it all work together seemlessly. And it has to not leak information to anyone except your bank which obviously needs to have the information anyway... and there is no smart phone app on the market other than ApplePay which can make that guarantee. Certainly not Google Wallet. Or CurrentC. Or anything else. And it's better than chip-and-pin and tap-to-pay which both have physical security issues (though they are much better than mag stripe).

Android is missing too many pieces and it will be at least 1-2 years before it has them all. And even then there will be such a huge percentage of *new* android phones that won't have all the pieces that it will only create mass confusion for the general consumer.

The reason Google Wallet has been a failure to-date is that it (and all other smartphone-based payment systems except ApplePay) is simply not convenient to use compared to swiping a credit card. The reason ApplePay became the #1 smartphone payment mechanism overnight is because it's utterly trivial and convenient to use.

It took me exactly 3 seconds at the local Whole Foods to pull out my phone, tap it with my finger on the finger print reader, and put it back in my pocket. It takes me about as long to swipe my card if I don't have to sign, but half the time I do have to sign so ApplePay immediately wins because I never have to sign (at least not so far).

Eventually all smart phones will do it the Apple way. For now, though, and for the next 1-2 years at a minimum, Apple is the only smartphone game in town that actually works well. Chip-and-pin and tap-to-pay cards work almost as well... they can even be more convenient in some situations, but they don't cover all the security bases.

-Matt

Comment: Thanks to Everyone! (Score 1) 928

by ewhac (#48286095) Attached to: Ask Slashdot: Can You Say Something Nice About Systemd?

Well... All told, I think that went rather well.

I wanted to chime in and thank everyone for participating in what was clearly an insane exercise in trying to cut through the acrimony and vitriol and get some actual information on what systemd is and what it's trying to do. You can't always grok what complex things are about just from the docs. That's why I wanted actual first-hand experiences from people who could point to actual gems they'd found.

To respond to some recurring remarks throughout the comments:

  • "Obviously a pro-systemd shill."
    No, I'm not shilling for RedHat or Poettering. In fact, I gave Poettering some stick for the whole corrupt-binary-logs-aren't-a-bug thing a couple weeks ago. I was being forthright in the opening paragraph: The simple fact that systemd has been widely adopted despite widespread protest made me genuinely wonder what I was missing that I hadn't figured out from the docs I'd read. So, no, there's no conspiracy here.
  • "Who are you to establish posting rules?"
    Well, gosh, sorry, but I was trying to save everyone time. Seriously, tell me you haven't gone, "Oh, ${DEITY}, another systemd thread; there goes my afternoon as I pick through the rat's nest of comments." So I hoped -- perhaps naively -- that requesting some organization would let us all get to the meat of issues of interest fairly quickly. And enough people did choose the follow the rules that the discussion overall turned out valuable (for me, anyway).
  • "Why do you dislike something you admit you know nothing about?"
    For largely the same reason I dislike Windows without having comprehensively pored over the "design" docs for COM, DCOM, MFC/ATL/WTL, WDM, NTFS, NTLM, Direct${THING}, Active${THING}, etc. etc. etc. Poorly-designed systems seem to have a certain "pattern" to them, and systemd at first glance seemed to match that pattern (the use of Windows-style INI files syntax didn't help, either). But the people adopting systemd are clearly not idiots, so I hoped people with actual experience with the thing could convey insights that (for me) the docs so far have not.
  • "You're thinking of the ads for Miller Lite, not Bud Light."
    *headdesk* I would like to apologize to a no doubt deeply irritated TV ad executive for completely misattributing their fifteen-odd years and millions of dollars worth of loud beer ads to the wrong company (I think this speaks well to my socially-isolated geek cred, though :-) ).

In the best tradition of USENET, I thought I'd summarize the highlights of what I got out of the whole thing. Most of the good posts have already been modded up, but the ones that especially stood out for me were these:

Thanks again to everyone who chimed in. You've given me a lot to read up on...

Comment: Re:It freakin' works fine (Score 1) 928

by ewhac (#48285843) Attached to: Ask Slashdot: Can You Say Something Nice About Systemd?

Think back to the epic holy wars of the past. Emacs vs. Vi. Big vs. Little Endian. Motorola vs. Intel. Amiga vs. Atari ST. ASCII vs. EDBIC.

vi*. Little-endian. Motorola. Amiga. ASCII**. Obviously.

(* with great respect to those who are able to use EMACS well.)

(** Seriously, who not using punched cards ever actually liked EBCDIC?)

+ - Say Something Nice About systemd 4

Submitted by ewhac
ewhac (5844) writes "I'm probably going to deeply deeply regret this, but every time a story appears here mentioning systemd, a 700-comment thread of back-and-forth bickering breaks out which is about as informative as an old Bud Light commercial, and I don't really learn anything new about the subject. My gut reaction to systemd is (currently) a negative one, and it's very easy to find screeds decrying systemd on the net. However, said screeds haven't been enough to prevent its adoption by several distros, which leads me to suspect that maybe there's something worthwhile there that I haven't discovered yet. So I thought it might be instructive to turn the question around and ask the membership about what makes systemd good. However, before you stab at the "Post" button, there are some rules...

Bias Disclosure: I currently dislike systemd because — without diving very deeply into the documentation, mind — it looks and feels like a poorly-described, gigantic mess I know nothing about that seeks to replace other poorly-described, smaller messes which I know a little bit about. So you will be arguing in that environment.

Nice Things About systemd Rules:
  1. Post each new Nice Thing as a new post, not as a reply to another post. This will let visitors skim the base level of comments for things that interest them, rather than have to dive through a fractally expanding tree of comments looking for things to support/oppose. It will also make it easier to follow the next rule:
  2. Avoid duplication; read the entire base-level of comments before adding a new Nice Thing. Someone may already have mentioned your Nice Thing. Add your support/opposition to that Nice Thing there, rather than as a new post.
  3. Only one concrete Nice Thing about systemd per base-level post. Keep the post focused on a single Nice Thing systemd does. If you know of multiple distinct things, write multiple distinct posts.
  4. Describe the Nice Thing in some detail. Don't assume, for example, that merely saying "Supports Linux cgroups" will be immediately persuasive.
  5. Describe how the Nice Thing is better than existing, less controversial solutions. systemd is allegedly better at some things than sysvinit or upstart or inetd. Why? Why is the Nice Thing possible in systemd, and impossible (or extremely difficult) with anything else? (In some cases, the Nice Thing will be a completely new thing that's never existed before; describe why it's good thing.)

Bonus points are awarded for:

  • Personal Experience. "I actually did this," counts for way more than, "The docs claim you can do this."
  • Working Examples. Corollary to the above — if you did a Nice Thing with systemd, consider also posting the code/script/service file you wrote to accomplish it.
  • Links to Supporting Documentation. If you leveraged a Nice Thing, furnish a link to the docs you used that describe the Nice Thing and its usage.

We will assume out of the gate that systemd boots your system faster than ${SOMETHING_ELSE}, so no points for bringing that up."

Comment: An alternative (Score 5, Insightful) 572

by pjrc (#48220685) Attached to: FTDI Removes Driver From Windows Update That Bricked Cloned Chips

Today Atmel, Microchip and others make inexpensive microcontrollers with native USB peripherals. The Atmel "8u2" chip, for example, is less expensive than even most of the FTDI clones, and certainly a LOT less than a genuine FTDI chip.

For years, I've published a very simple and easy-to-use USB code for those chips.

http://www.pjrc.com/teensy/usb...

I also publish a signed INF installer that works with ALL USB Serial based on this standard protocol (called Communications Device Class, Abstract Control Model, or CDC-ACM). All 3 operating systems have the necessary driver built in. Mac OS-X and Linux load it automatically. Windows needs the user to add a INF.

http://www.pjrc.com/teensy/ser...

Sadly, the CDC-ACM driver in Windows (called USBSER.SYS) is buggy. About a year ago, I sent Microsoft this reproducible bug report.

https://www.youtube.com/watch?...

In a follow up email a few months ago, they were supposedly testing a fix. I'm hopeful that Windows 10 may be the first version of Windows to ever ship with a good quality USB Serial driver (as Linux has done for many years, and Apple as done since releasing Lion a few years ago).

Felson's Law: To steal ideas from one person is plagiarism; to steal from many is research.

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