brainchild

@TomYan, Let me try again. Does the mount attempt block until all devices are available for the target volume? If so, then why is it failing in my case, during certain boot sequences, according to the race condition, because one of more of the devices is not yet available? That the mount fails suggests that the sequence is designed such that all devices should be available when mounting is attempted.

@TomYan, If the kernel is simply waiting for device availability in order to mount, and if arrays are handled through a workaround handled by the file system, then why is mounting failing in my case for an incomplete array, based on the device becoming available only in the future with respect to the attempted mount?

@TomYan, Device registration in the kernel may occur through various layers, but relevant to the current discussion is a device being present in devpts and available for mounting. The boot process is sequenced to prevent race conditions for mounting local volumes.

@u1686_grawity, You write, "The boot sequence only needs to wait for that specific device to appear". I respond, 1) a failed mount may be reported only after all devices have been scanned, and 2) by now a common use case is mounting a multi-device volume identified by not by device addresses but by identifier written on the device, that is, a UUID. In fact, for the latter case, only one device of the group may be given by its address.

@TomYan, Sorry, but your assertions are hard for me to understand as accurate. For a local SCSI controller and disk holding a file system, the boot sequence would ensure the device being registered in the kernel before an attempt to mount. Otherwise, all Linux systems, as a matter of course, would fail to boot intermittently, due to such a race condition. If a SCSI device is would be discovered at boot, then it will be so before the mounts are processed. The difference for network devices is simply that certain operations must follow loading the network stack.

@TomYan, Scanning for devices is a set of events that concludes at some definite point in time. It is only after such point that mounting should be attempted. The mounting operation should begin after the device controller (e.g. iSCSI) has completed scanning for all devices.

@TomYan, The issue is particular to iSCSI, because mounting in general is deferred until after scanning of physical block devices is complete.

@TomYan: The issue is not one appropriately addressed with the file system tools. The storage controller drivers (e.g. iSCSI) resolve when the device scan is complete. The file system may only address whether a mount is viable.

@TomYan, Btrfs scans devices currently registered in the kernel that match a UUID. If no device is found with metadata matching the ID, or if the metadata written to any matching device refers to devices not present, then mounting fails. The mount operation does not wait for devices to become available. Such behavior has never been expected. Device discovery must complete before mounting is attempted.

@TomYan, The volume itself spans multiple physical devices. The devices associated with the logical volume are changed frequently, sometimes added, and sometimes removed. Of course mounting volumes on the network block devices must occur synchronously only after all devices are scanned. Otherwise, each boot sequence would inevitably be bound to a race condition, as is the premise of my issue.

Both Requires and After have been given. The devices themselves are changed frequently, and so referencing them in the unit descriptor is not feasible. I wish the mount to activate when no more devices will be attached through the initialization of the iSCSI service.

@TinfoilHat. I'm sorry, this exchange is not productive. You appear to be giving equivocations, tangents, and evasions, more than addressing any immediate question. (The question meant What does what you just wrote have to do with my examples? Is that not plain?)

@TinfoilHat, What does it have to with my examples?

@TinfoilHat, Yes. Quoting your text: "Which is best used restrictively only when it is preceded by a preposition {the situation in which we find ourselves}." It would seem you have indicated that the preposition was I feature of my example. Was it an error?

@TinfoilHat, Are you identifying the immediate situation as one in which which "is preceded by a preposition"?

@TinfoilHat, Do you think the article answers the question?

@StuartF, Have you found any direct duplicates? I haven't even an inkling of what would be suitable search criteria.

@David, It means the overarching intention of the subordinate clause is to add description, rather than to impose restriction.

@David, You do understand, right, that an understanding of the distinction in the most common case is a stated premise of the question? Do you find any previous questions that address the same issue, or do you suggest simply that any answer on the general subject will elucidate the narrow issue as well?

I have no wish to debate some canonical understanding of terminology. I am following a practical understanding that the desktop computer is the name given to the successor of the microcomputer, even if no hard boundary is identified. Apples and PCs were desktops, not microcomputers, in the popular lexicon, which is completely adequate for the current discussion.

As I indicated, I am content that the vernacular terminology is expressive enough to convey the essence of the question. I have no wish to quibble over definitions.

Raffzanh: Is it not clear from context that the relevant period would be bounded roughly by video terminals becoming prevalent, and desktop systems, which have integrated video adapters, replacing microcomputers and minicomputers?

@Raffzahn The evolution of computer equipment had already become a fiercely competitive an innovative space, with the market demanding new capabilities at lower cost every several years. I doubt complacency was the reason for such developments not occurring until decades after they would have been feasible.

@snips-n-snails: I suppose the question might be framed as you have done, but I would rather see the video adapter as a choice, not an invention, as plainly Job's team was not the first to conceive of it, or even to build it.

It's hard to see how two devices is more economical than one even if the assumption would be robust (and it seems not so to me) that the total memory required for both configurations is the same. At minimum, achieving the same functionality without an additional processor, as appearing in later terminals, would seem to be a big savings.

Would it not have been cheaper for the video interface to be integrated into the host, obviating the need for memory and processing the peripheral?

Two readers have given comments that suggest some kind of confusion. Accurate and direct comprehension by readers is the only relevant measure of clarity. I will attach a note to the answer, and let readers judge for themselves.

I'm not following the meaning of your comment or how it might relate to any open question. If I may offer a suggestion, you might replace, in your current answer, the word "non-countable" (which anyway is not preferred, in contrast to "uncountable"), with the phrase, "appears in the singular form". I believe that even such a small change would resolve the entire confusion.

The confusion is that you seem to mean that the word appears in a singular form, which is clear and accurate, but you explain it as the word becoming uncountable, which is unclear and unsupported.

(Also, the suggestion that English speakers know "instinctively" how to make a plural form, but none has ever created written instructions in a reference guide, seems to be easily refuted by a simple web search. I would suggest using the search keywords "english plural", if you feel unsure where to start.)

@Lambie: My first comment narrowly addressed Sergey's question. It had no further relation to your answer. You chose then to argue that chair has uncountable usages. My other comments addressed that claim. Since you appear to be, for some reason, upset by this exchange, I'll leave to others to decide what is clear, accurate, or useful.

@Lambie: Refer to explanation for uncountable: "A noun that cannot be used freely with numbers or the indefinite article, and which therefore usually takes no plural form." Note the distinction between the noun, and its form.

@Lambie: The word chair is countable. If not, the definition would indicate otherwise for some or all usages. (For comparison, see wine, sand, and fun). That uncountable nouns may appear in some sentence not having their plural form is irrelevant. You appear to conflate the form of a word, which may be singular or plural, depending on the word, with the word itself, which may be defined as countable, uncountable, or both.

@Sergey: Whether a noun is countable is a property of the word, not the usage in some sentence. Generally, any noun word is either countable or not countable. The dictionary definition indicates which one. (A few words have usages that include both the countable and noncountable cases. If so, the dictionary will indicate both, sometimes each separately according to usage in the definition. Consider wine and sand.) The word chair is always countable, regardless of usage in the sentence. If it seems uncountable, then the reason is that the grammatical context requires a singular form.

thanks for your time

so how do two people get different morality even though they share the same basic values?

but it's also possible that two individuals have different ideas about what is or isn't moral?

so morality is related to conscience which is based basic values that everyone has?

but those values are not related to morality?

so what could you tell someone in order to appeal to his conscience?

if the convicted person said he doesn't understand his acts to be immoral, would you be able to explain to him why it is immoral?

if someone committed a murder then i assume you would want that person to be punished?

so for you morality is just how some particular individual perceives that others expect him to behave?

i'm just trying to understand, if morality is different from one person to another, then how does it succeed in informing us to behave toward each other?

but with separate systems that may be incompatible could you resolve how one person should act toward another?

maybe you didn't

i thought you said that morality describes how to act toward others based on their common expectations?

so you would have one kind of morality and he would have another?

sure, but if you asked someone what he considers moral and he said something that didn't mention god, then you would say it's not moral?

but do non-Christians value it as moral?