WD Explains Its Windows-Only Software-Based SSHD Tech 286
crookedvulture writes "Seagate and Toshiba both offer hybrid hard drives that manage their built-in flash caches entirely in firmware. WD has taken a different approach with its Black SSHD, which instead uses driver software to govern its NAND cache. The driver works with the operating system to determine what to store in the flash. Unfortunately, it's Windows-only. You can choose between two drivers, though. WD has developed one of its own, and Intel will offer a separate driver attached to its upcoming Haswell platform. While WD remains tight-lipped on the speed of the Black's mechanical portion, it's confirmed that the flash is provided by a customized SanDisk iSSD embedded on the drive. The iSSD and mechanical drive connect to each other and to the host system through a Serial ATA bridge chip, making the SSHD look more like a highly integrated dual-drive solution than a single, standalone device. With Intel supporting this approach, the next generation of hybrid drives appears destined to be software-based."
Win modem (Score:5, Insightful)
Re:Win modem (Score:5, Funny)
Here's [angband.pl] my dissertation on winmodems. Should apply well to windisks too, I guess.
Sweet! (Score:2)
Re:Win modem (Score:5, Interesting)
Except these disks are more standard. They're basically an SSD and a HDD hooked to a SATA multiplexer (that lets you connect more than one SATA device to a SATA port. NOTE: Note all controllers support MUXes. Also, both drives share the bandwidth of the upstream port).
So plug this into a Windows PC and install the drivers, and two drives become one. Plug it into a Linux PC and you see two drives. Plug it into a Windows PC without drivers and again, you get two drives.
Re:Win modem (Score:5, Insightful)
Except these disks are more standard. They're basically an SSD and a HDD hooked to a SATA multiplexer (that lets you connect more than one SATA device to a SATA port. NOTE: Note all controllers support MUXes. Also, both drives share the bandwidth of the upstream port).
So plug this into a Windows PC and install the drivers, and two drives become one. Plug it into a Linux PC and you see two drives. Plug it into a Windows PC without drivers and again, you get two drives.
I would be concerned about how accessible my data was without the drivers. So you're using Windows and your data is partly on the platter and partly on the SSD; you reboot to an OS without the driver (i.e. the driver breaks when you upgrade Windows, you boot into Linux, whatever) - can you still get at your data. My guess would be that whilst the contents of the drives will be accessible as two independent drives, they will be in some undocumented format and therefore irrecoverable.
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Re:Win modem (Score:5, Insightful)
Too often it means it wont work with windows either. My brother-in-law lost all his peripherals when he upgraded from Windows ME to Windows XP. He had to buy a new printer, scanner and modem. He said he didn't mind though as at least he could run the computer for more than 30 minutes without a blue screen. I remember how happy he was that it would run for several days without a reboot and that he could actually turn it off without pulling the plug. I've got a car programmer that has to have XP. I keep an old laptop that has as it's only purpose to run that programmer. Imagine when you upgrade your windows software and the driver for this drive no longer works.
Re:Win modem (Score:4, Funny)
Your brother-in-law got Windows Me to run 30 minutes before it blue-screened? Amazing.
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Most of the scanners and printers I've bought have been used and hit the market because someone made an OS upgrade and they were no longer supported. In the case of the HP scanners this is particularly egregious because some of the old ones speak protocols they're still using, and they simply disable them in the new driver to force upgrades. Works for me, though.
Re:Win modem (Score:5, Funny)
Hey, it's right along the lines of a software raid controller that only works in Windows. Awesome...
Comment removed (Score:5, Insightful)
Unclear whether this is a problem or not... (Score:5, Interesting)
It isn't clear, exactly, from TFA what the drive will look like when you plug it in. Both components(the HDD and the SSD) apparently can function as SATA peripherals; but they are both behind some sort of bridge chip, type unspecified.
If the 'bridge chip' is just a reasonably generic SATA port multiplier, then an unsupported OS, or Windows without the driver, will just see two drives, the larger mechanical one and the smaller flash one. This would leave the way open for any OS with SATA and AHCI support to do whatever it prefers to get the best performance(on Linux, I assume that'd be at the filesystem level, with something like btrfs)
If the 'bridge chip' is some sort of proprietary oddity, and the vendor driver is required to even communicate with the flash portion(presumably at least some part of the drive will be visible as a normal SATA device, or booting without specific BIOS support would be a problem...), then that's pretty much worthless.
Re:Unclear whether this is a problem or not... (Score:5, Interesting)
Unclear whether this is a problem or not...
IMO it's a problem either way. The Intel "Smart Response" stuff that they introduced as a chipset feature a year or two ago (you put a HDD and SSD in your computer and it will cache stuff on the SSD) works similar. A neat idea, but a non-starter for what I wanted. Why?
Even if it works fine in Windows and works fine in Linux, it may still not really work if you want to dual boot. If you want to be able to use the SSD cache in both operating systems, they have to be able to not step on each others toes. If you want to be able to read data from the other OS, it has to be able to understand the format the other is in. (Potentially this could be "doesn't have to do anything in particular" if you make it a write-through cache, but write-back caches might have more stuff. And you still need to understand the format to write if you have a write-through cache.)
Obviously not everyone needs dual booting, but not everyone needs Linux support either. It's a bit selfish to say that it's a problem if there is only support in Windows, but it's not a problem if there is support in both OSs but the support isn't compatible. :-)
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Re: Unclear whether this is a problem or not... (Score:2)
I don't see why it should clear it. If I had however much GB of my most popular files in a non volatile cache, I would most definitely want fast access to them during boot.
It is a huge problem (for free software) (Score:5, Insightful)
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Son, it's time someone explained the facts of life to you.
There are two and only two kinds of vendors in this world:
1. Those who want my money, and
2. those who don't.
Which category do you think those vendors who attempt to offer me Windows-only solutions fall into?
It's stupid though (Score:5, Insightful)
The nice thing about Seagate HHDDs or SSHDs or whatever the companies what to call them now is that they just work. You drop it in a system, it works like a normal drive but faster. The flash works like cache on a RAID controller or the like. It just speeds things up.
With this, there's mucking about. Even if you could use it as separate drives, why would you want to? If I want to to just some small SSD storage and larger magnetic, I can. In fact I do. In my laptop I have a SSD for OS and apps and an HDD (actually one of Seagate's hybrids) for media and samples. My desktop is the same but more and larger drives.
It just seems silly to me. An all hardware approach seems much better and clearly doesn't cost that much as Seagate's drives are not expensive.
Re:It's stupid though (Score:5, Funny)
Don't you see? WD has invented the idea of having an SSD and an HDD show up as separate devices! It's ingenious! Next they're going to move beyond computers and re-invent the classic Swiss army knife. Instead of having all the tools inconveniently stuck together, they'll have a bunch of separate tools in a box!
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Exactly. And in terms of "knowing" what to put in the cache, the drive knows just as well as anything else what should be there - because it knows what sectors have been hot. The filesystem on top is pretty irrelevant.
I've been pretty happy with my Seagate Momentus XT 750, which works this way. I'm not sure if they do write caching or not yet, but that would clearly help, as would some more NAND. Early days yet, but if seagate can get say, 32GB of NAND and write caching on a new 2TB drive, sign me up
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The most notable example being SATA on Intel chipsets:
http://communities.intel.com/message/133881 [intel.com]
If Intel wanted to, they could probably have a new driver that enables support for port multipliers before WD releases the disk.
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If that is the case then a Mac would be able to use it as a fusion drive.
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It isn't clear, exactly, from TFA what the drive will look like when you plug it in. Both components(the HDD and the SSD) apparently can function as SATA peripherals; but they are both behind some sort of bridge chip, type unspecified.
If the 'bridge chip' is just a reasonably generic SATA port multiplier, then an unsupported OS, or Windows without the driver, will just see two drives, the larger mechanical one and the smaller flash one. This would leave the way open for any OS with SATA and AHCI support to do whatever it prefers to get the best performance(on Linux, I assume that'd be at the filesystem level, with something like btrfs)
If the 'bridge chip' is some sort of proprietary oddity, and the vendor driver is required to even communicate with the flash portion(presumably at least some part of the drive will be visible as a normal SATA device, or booting without specific BIOS support would be a problem...), then that's pretty much worthless.
If their target market is Windows, then it is reasonable to assume that their target market is or includes desktops and laptops. At a guess, the disk will be readable from the BIOS for boot purposes (not much good if it only works as a second disk!), so it must be some sort of bridge that the BIOS doesn't care about... time will tell I guess.
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If the 'bridge chip' is just a reasonably generic SATA port multiplier
A transparent bridging scenario such as this would not make much sense as an SSD can easily saturate the available bandwidth of a 6 Gb/s SATA port. A non-transparent bridging scheme which makes the device look more like a traditional spinning HD with a really big cache would make more sense as the SATA port driver would not have to route every sector write/fetch to specific device. Most likely the driver on the OS side only manages migration of data between the SSD and HD to balance read/write performance f
Stop. Hammer time. (Score:5, Insightful)
The iSSD and mechanical drive connect to
I believe I speak for the majority here when I say.... D'ARGH! KILL IT WITH FIRE NOW! This is yet another pathetic attempt by WD to marry it's crappy line of mechanical drives to SSDs in order to stretch their relevance out a little bit longer and keep them from having to retool their assembly lines and such to produce SSDs exclusively. Weeeell, good for you guys. But as my father would say: "Shit or get off the pot." Either switch to SSDs, and eat the cost, or stick with mechanical drives because they're cheap. But don't waffle and try to do both; You're getting the worst of both worlds then.
Re:Stop. Hammer time. (Score:5, Insightful)
>You're getting the worst of both worlds then.
No. With SSD caching you get all the capacity of rotating disks with > 80% of the speed of SSDs.
That is not the worst of boths worlds. It is the best of one and most of the other.
Re:Stop. Hammer time. (Score:5, Interesting)
No. With SSD caching you get all the capacity of rotating disks with > 80% of the speed of SSDs.
That is not the worst of boths worlds. It is the best of one and most of the other.
No; You can achieve that with a separate SSD and a mechanical drive; That's what most people are doing now anyway.
By putting the two together, what you're basically getting is a mechanical drive with a massively large cache. And because you now have two drives married behind a single logical interface, you've decreased the life expectancy further -- if either fails, it's a boat anchor.
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Boat anchor? How large do you think these drives are?
Re:Stop. Hammer time. (Score:5, Funny)
Boat anchor? How large do you think these drives are?
Have you considered he might have a really, really small boat?
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Yes. The only thing that is different is that the SSD and drive is not separable.
I would not choose this product. I choose mirrored rotating disks and one SSD cache.
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No; You can achieve that with a separate SSD and a mechanical drive.
I can't do that. My laptop only has one drive bay.
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Then you don't want spinning platters in your laptop draining your battery, you want a full on SSD that just barely sips power with no speed loss.
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Then you don't want spinning platters in your laptop draining your battery, you want a full on SSD that just barely sips power with no speed loss.
What if you have need for a hefty amount of storage without paying through the nose? You can get a 1 TB hybrid laptop drive for much less than the cost of a full SSD that's a quarter of the size. Or a 500 GB hybrid for just a little bit more than a 128 GB SSD.
Obviously not everyone needs that space, but I certainly would if my main computer were a laptop.
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Though I have to remove the 3G card to put in the drive, but I don't us
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First, the SSD-HDD concept has proven itself, IF it's done right. When the Seagate Momentus XT was new, its write performance was better than many other SSDs it was compared to in benchmarks at the time, with read performace that comparable. (Of course, since then Seagate said they would stop making 7200 rpm drives, which means that isn't likely to happen again.)
I don't know whether the "two disks with a bridge" idea is "done right", though. I gue
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It's chance of failure and multiplier effect (Score:3)
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No, I understand completely how it works, you just didn't read my post very well...
If the MTBF of one is significantly longer than the other the total MTBF doesn't really change.
Eg. (with totally made up numbers, which really aren't even representative of the types of statistical analysis used in manufacturing) if the HDD has a 1% chance of failure per year and the NAND flash chips have a 0.1% chance of failure, the combination is just not significant (especially vs. the performance advantage gained in thei
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Oh, and I hate to reply twice, but I hit send before making the most important point...
Further complicating the "statistics" is the fact that the NAND "cache" will totally change the usage profile of the mechanical drive. If the cache hit rate is high, that's a lot less seeks on the drive. If the drive is the most likely component to fail, that could significantly INCREASE the MTBF, not decrease it. Again, the original post was really the one that "didn't stop to think about it" (and in yours you did st
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incorrect trick question.
WD makes great drives, for specific purposes only. These drives are not them.
The WD red drives are acceptable. aside from that, not much for hard drives..
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That'll be a winner... (Score:2)
... in all the big Fortune double-digits, that have their data centers overflowing with Linux servers.
The worst part of this, is that when WD goes bankrupt, as a result of this brilliant business strategy, there'll be even less competition in the HD market, which always means higher prices.
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No the worst part will be bringing flaky driver issues to hard drives. What's to say the next version of Windows will even work with the thing. Hell, I can't even trust MFGs to put out drivers that actually work with Win7 for something as simple as a USB interface. I downgraded to Win7 from Win8 on new hardware and wound up having to use a Linux Live CD on that system because the open source WIFI and USB drivers worked out of the box (the same chipset was in a different piece of hardware that had an ope
I like WD drives (had good luck with 'em) but... (Score:5, Interesting)
As an end-user, I'm NOT going to put up with a solution like this.
Even if it somehow performs better than current hybrid drives.
Even though most of my work is done on a Windows platform.
Hybrid drives are already a big compromise for minute gains.
Tying it to an OS choice?
NO FUCKING THANKS WESTERN DIGITAL!
In a budget situation I'd rather just put up with a competitor's hybrid or a plain old mechanical disk.
In a performance situation I'd rather just spring the extra cash for a real SSD. Better returns and more flexible.
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Heaps of people seem to think this is the same thing... but it is an extremely inefficient way of utilizing your space - if you have a 2GB file with only say, 100 MB of which is "hot" then you are moving the entire 2GB file.
A controller / driver / intelligent operating system can determine which BLOCKS in the file need to be cached, so in the above example, instead of consuming 2GB
Wait, a hard drive with SSHD? (Score:5, Funny)
WD has taken a different approach with its Black SSHD
They'll have a lot more explaining to do, once some hacker, cracks the SSH password, starts pwning WD disk drives, and they begin to spew forth spam... :)
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It's a feature. Once they hack it they start using it as cloud storage for their porn. Saves you the effort of finding and catalogueing the porn yourself. Just log in and browse around, every day will be an adventure!
RAM (Score:2, Interesting)
And its worth reminding people, that Windows already caches stuff in RAM, if you had 24GB of ram then it would be a lot faster cached, and the only gain with these drives is on startup and then not by much (since Windows arranges the disk so the common items are close together ready for boot).
So WD simply remind everyone why hard disk makers are struggling to remain relevant.
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This part probably doesn't help WD as much as they would like(since they had to buy the SSD silicon from a different vendor, who presumably is eating a nontrivial percentage of the profit on the drive); but one of the reasons why Flash-based solid state storage is popular is that it is faster than mechanical; but a lot cheaper than RAM. Even assuming your system isn't socket-limited or 32-bit non PAE, 24GB of RAM(basic DDR3, no ECC or other fancy stuff) is ~$200. 24GB of SLC Flash, from Intel, is ~$120, and
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I have 16 GB on my laptop, and rarely pass 8GB in use. Making an 8GB RAM drive and loading the OS into that partition would make a huge difference in system performance.
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No, 24GB RAM is $60, not $200. I just bought 4GB sticks of DDR3 for 300 baht retail, = 6*$10 = $60.
Where the heck did you find that?
Since he paid in baht, I'm guessing somewhere in Thailand.
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Yeah, write cache is turned off in Windows by default for good reason: if you had say 20 GB worth of writes in RAM which hadn't yet hit the disk, guess what happens when the power drops or your OS crashes? RAM is fine for READ cache, but caching writes, dubious. Which is why enterprise level storage gear uses NVRAM, battery backup, etc. And even if you turn on write caching, if an application forces the filesystem to sync and verify the data was written, it will be flushed anyhow.
Eventually, you need
choice? (Score:2)
only in black?
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Windows only? (Score:4, Informative)
Uh, okay, whatever.
Guess I won't be buying one. Best of luck to those that do.
Why bother? (Score:3)
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I use SteamMover to copy over games that have loading problems to the SSD. http://www.traynier.com/software/steammover [traynier.com]
It's "ancient" now but still works great : )
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Many new laptops support a mSATA drive. Even my current-gen 12.5" Thinkpad supports one in addition to a normal 2.5" drive. While these are not usually extremely high performance or capacity, you can get a ~250GB model that operates at around SATA 3gbps speeds without looking too hard. In any case, a mSATA SSD plus a normal hard drive will likely be better for most users.
Oh boy Winmodems (Score:2)
Wonderful idea. I can't wait to run right out and buy that. /sarcasm
Do Not Want (Score:3)
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It's not "lazy shits," it's "bean counters" that say software is cheaper than hardware always.
It's also the Intel-Microsoft cartel trying an end run around anti-trust laws to lock out competitive operating systems.
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Will the world implode? (Score:2)
Now if only we could pre-populate the buffer cache (Score:2)
Like make the OS learn what stuff we usually read from the drive, and keep that stuff handy. That would be so cool!
No one ever got fired for buying IBM.... (Score:2)
This is all a bunch of stupid shit (Score:3)
In my computer, I have a Crucial M4 SSD for the boot drive and the more speed fasterness "crucial" apps. Then I have a WD Black terabyte drive for all the shit that doesn't need to be maximum possible speed.
Sometimes, I change my mind what needs to be faster than what is not at the forefront of my mission anymore. That's when I move my files around manually. Mind you, these are usually 8 - 20 GB of files or whatnot. This type of operation I do not want an un-brained background process to be performing at random times. If it picked the wrong time, I might drop FPS in an online match that was worth so many imaginary dollars to nobody at that precise moment...
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Re:This is all a bunch of stupid shit (Score:4, Funny)
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History will repeat itself. (Score:2)
Remember those great Intel software-based modems back in 1993 that Intel had for Windows 3.1 that weren't supported by any operating system afterwards?
Remember how Intel sold that line of business and left us all hanging? Yeah.
Software based hardware like this is destined to be a one-trick pony. Use it in one system, and then it's stuck on that operating system for the duration. You'll be left in the lurch when the next version of you OS is released.
Go ahead and line-up to get screwed by WD and Intel. I
Meh (Score:4, Insightful)
With how much straight SSD prices have dropped over the past few years, I don't even really see much need for a hybrid drive. In 2011 I bought a 60gb ssd for $95 ($1.58/gb). Today, I can buy a better performing 500gb ssd for $350 ($0.7/gb).
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SSD's suffer from one fairly critical problem: Longevity.
As densities become higher (and process sizes smaller), reliability with SSD's will only decrease from its already horribly poor state.
I'm sure you're probably thinking "but improvements in technology will bring greater reliability!" Unfortunately, we're at the point where quantum tunneling starts screwing with us, and there's little we can do about it. Heisenberg's Uncertainty Principle is a brick wall, and we've run smack into it. Quantum tunneling
Re:Meh (Score:4, Insightful)
Re:WHAT (Score:5, Informative)
Nice troll, btw.
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Since OSX and Linux already do this, maybe only Windows needed a driver.
Re:WHAT (Score:5, Insightful)
Even if I ran windows I can't see having a driver for my hard drive. It should just work no matter what OS I am running. Sad and stupid. That's okay though as for me I don't think the hybrid is the way to go. SSD for the OS and external platter type for storage. Like most compromises this seems like the worst of both worlds.
Re:WHAT (Score:4, Insightful)
Yeah, a drive that depends on any kind of OS besides the bare metal firmware on the board to which it is attached makes me uneasy. There are just so many more answers to the "what could possibly go wrong" question.
Re:WHAT (Score:5, Insightful)
Similar question: Which would you rather have: software RAID or hardware RAID? On Linux, software RAID is usually faster, cheaper, more reliable, less buggy & fuller featured.
So yes, I'd prefer the drivers in my operating system rather than buried in some inaccessible firmware somewhere.
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Re:WHAT (Score:5, Informative)
The dm-cache [kernel.org] device mapper target was added to the kernel in Linux 3.9 [kernelnewbies.org]. bcache is apparently on track for 3.10 [lwn.net]
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shut the fuck up i'm not a troll, you're a fucking troll.
that software you linked to is not FREE as in speech.
Even Speech comes with a price.
Re:osx? (Score:5, Informative)
I see that you don't really understand what Apple's Fusion Drive really is. In Intel's SRT the SSD drive acts like a cache for the HDD [anandtech.com]. I hope I don't need to explain what a disk cache [wikipedia.org] is and how it works. In the Fusion Drive [arstechnica.com] on the other hand both drives appear as a single logical volume with the space of both drives combined and the OS decides which files get stored on the SSD and which on the HDD. From the Ars Technica article I quoted:
In a caching solution, like Intel's, files live on the hard disk drive and are temporarily mirrored to the SSD cache as needed. In an enterprise auto-tiering situation, and with Fusion Drive, the data is actually moved from one tier to another, rather than only being temporarily cached there.
Those are two very different approaches.
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