Are cheap 2.5″ external hard disks constrained to Exfat and incompatible with Time Machine? Is this a physical limitation / hardware issue?

I bought two 2TB 2.5″ external HDDs that came with the following warning message in a Readme file contained in the drives.

“The drive can only be formatted with Exfat and cannot be formatted in other for mats, suchas NTFS, FAT32, FAT. Otherwise it will cause the hard drive t be unusable!
This hard disk is only suitable for windows system and XP system not suitable for PS4, xbox macbook,tv, etc.
The disk needs to be inserted into the USB interface of the device’s motherboard. If the transfer method is used, there may be insufficient power supply to the disk.”

Both drives appeared to work straight out of the box. However, I got errors when trying to partition them (I use a MBP, mid-2015 Retina, MacOS 10.3.3). Now one of the external drives has become unusable. So…I’m guessing this could be because these are cheap no-brand drives which I ordered from China, similar to these:

And I’m guessing the manufacturer has assembled them or configured them in this way (limited to Exfat) in order to cut costs. My questions are:

  1. Why/how an external drive can be manufactured to be permanently only Exfat?
  2. Is this a hardware constraint or physical limitation imposed by the manufacturer or by the USB to SATA bridge used?
  3. Is there a way to overcome this so that I can use them for Time Machine backups?…Has anyone been succesful in backing up with Time Machine on these types of 2.5″ external hard drives?

From the Terminal query below, it appears that the drive is a JMicron device. I’ve now got in touch with JMicron and waiting to hear back (will post updates here). In the meantime, if anyone can shed any light and answer/respond to any of the above questions I’d very much appreciate it.

diskutil info /dev/disk1:

   Device Identifier:        disk1
   Device Node:              /dev/disk1
   Part of Whole:            disk1
   Device / Media Name:      JMicron Generic Media

   Volume Name:              Not applicable (no file system)

   Mounted:                  Not applicable (no file system)

   File System:              None

   Content (IOContent):      FDisk_partition_scheme
   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 USB
   SMART Status:             Not Supported

   Total Size:               2.0 TB (2000398934016 Bytes) (exactly 3907029168 512-Byte-Units)
   Volume Free Space:        Not applicable (no file system)
   Device Block Size:        512 Bytes

   Read-Only Media:          No
   Read-Only Volume:         Not applicable (no file system)
   Ejectable:                Yes

   Whole:                    Yes
   Internal:                 No
   OS 9 Drivers:             No
   Low Level Format:         Not supported

Below is a screenshot showing the readme file and the warning contained in it.

enter image description here

NB. Question asked earlier to try and restore the unusable drive here Unusable 2.5″ external HDD. Partition failed with the error -69760: Unable to write to the last block of the device. Exfat only? Repairable?).

sharepoint online – CSOM Utility.SendEmail() will only send email to office 365 email addressees… is it a limitation?

I have the following code inside my CSOM console application to send email:-

static private void sendemail(ClientContext context, string subject, string body, string email)
            var emailp = new EmailProperties();
            emailp.Subject = subject;
            emailp.Body = body;
            List<string> toUsers = new List<string>();
            emailp.To = toUsers;

            Utility.SendEmail(context, emailp);

now the email will be sent correctly incase the to email is defined inside office 365,otherwise no email will be sent. any idea why?

Inodes Limitation

I am bit not clear how Inodes limitation works with Reseller Hosting. I am taking Namehero’s limit of 300,000 inodes per reseller account as… | Read the rest of

unit – Limitation of the limits of Swing 1 and 2 in the joints of characters asymmetrically

I want to create a game object that looks like the creatures seen here. A CharacterJoint It's perfect for me, but I can't find a way to limit the swing 1 and swing 2 limits asymmetrically, which can easily be done for the swing limit.

One approach I tried was writing a script that will rotate the body beforehand and then add the joint. This did not work for me and I was wondering if there could be a simple way of doing this that I am missing. If there isn't, I'll add the script to my question.

csom: SharePoint online limitation issue

I recently faced an acceleration issue and based on the article below we should decorate the request with the User Agent

For all of our calls, we use ExecuteQueryRetry, which is the PnP extension method. Based on my research and the following article, PnP adds the default value ("NONISV | SharePointPnP | PnPCore / {PnP CSOM Core assemblyversion}") for the User Agent.

I tried to look around, but couldn't find any documentation that PnP adds this value.

  • Can anyone help me find documentation on the default value for User Agent if we use PnP CSOM?
  • I was also wondering if passing this value will not result in acceleration? or can it still happen?
  • What benefit can we get if we have a user agent value? Speed ​​or acceleration or both?

SI prefixes. what caused the limitation

why the minimum value is yocto ($ 10 – 24 $) and the maximum is yotta ($ 10 24)
Is this due to the fact that we haven't had to say enough about such big / small values?

control theory: why does a pole in the RHP impose a minor limitation on bandwidth?

I am studying control systems, and I have seen that a pole in the right half plane gives a limitation in bandwidth, imposing that the system bandwidth must be high enough.

My question is: why does this happen?

I have seen, for example, that for zeros in the right half-plane, the limitation is given by the fact that the phase decreases after a certain frequency, but why do I also have a limitation for a pole in the right half-plane?

Workflow: UI / UX in agile equipment versus technical design limitation

I am a team leader with decent programming experience. I learned basic concepts of user interface design during my studies, however, I am far from having experience in this field. So please forgive me my ignorance and / or misunderstanding of how things work πŸ™‚

I have trouble designing the best workflow for my team. We currently have a sprint where the UI / UX designer, who is working on the same function as the rest of the team. However, it seems that this flow is not efficient: the planning phase takes a long time (and I mean that it takes between 1.5 and 2 days to plan the 1-week sprint), and I feel that the technical talk about the developer It influences the design.
I was thinking of moving on to the "make the UI / UX run a sprint before" approach, however, I can't solve a problem:
On the one hand, I would like not to influence the creative process of the UI / UX design by technical details, but on the other hand, I fear that the designer will end up with things that are too expensive to develop (that is, we do not currently store X in our system, and adding that would add N weeks of additional work) and in the end you will be forced to do the work again (= wasted effort).

  • In case UI / UX knows the technological details or will disturb creativity
    process to much?
  • How do you handle that in your environments? You do
    have some kind of meeting where the UI / UX design discusses the proposal
    solutions with developers?


lo.logic – Can Ackerman establish the theory without a class construction scheme plus a limitation of the size axiom to test the consistency of ZF?

Take all the axioms of Ackermann's set theory, eliminate the class construction axiom scheme.

Add the size limitation axiom:

$ forall X forall Y [X in V land Y subseteq V land | Y | leq | X | to Y in V] $

Would the resulting theory prove $ V $ be a model of $ sf ZF $?

Should the caller be informed of the REST API rate limitation data?

I have a REST API, which has a speed limit of 1 query per IP for 5 seconds. When the user tries to call the API too often, I respond with the HTTP status code 429 Too Many Requests and a JSON message.

Now the question is, should I tell my API consumer the allowed rate, or should I return a generic message? Which of these is the correct form according to the REST principles?

  "error": {
    "message": "Too many requests"


  "error": {
    "message": "Too many requests, allowed only 1 per 5 second"