For this week’s e-newsletter, we’ll cowl:
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Design patterns cheat sheet
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6 methods to show code into lovely structure diagrams
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What’s a File Descriptor?
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Scan to pay in 2 minutes
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Direct funds
Flip python code into cloud system structure diagrams
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Era of diagram and flowchart from textual content in the same method as markdown
Instance:
Free editor: Asciiflow, dot-to-ascii
Paid editor: Monodraw
It’s an open-source software permitting customers to create diagrams from plain textual content language.
Visualize your Markdown as mindmaps. It helps the VS code plugin.
Create lovely system diagrams with Go
How can we work together with Linux Filesystem by way of file descriptors?
A file descriptor represents an open file. It’s a distinctive quantity assigned by the working system to every file. It’s an abstraction for working with recordsdata. We have to use file descriptors to learn from or write to recordsdata in our program. Every course of maintains its personal file descriptor desk.
The diagram beneath reveals the layered structure in Linux filesystem. Let’s take course of 1234 for instance.
🔹 In Consumer House
Once we open a file referred to as “fileA.txt” in Course of 1234, we get file descriptor fd1, which is the same as 3. We will then move the file descriptor to different features to write down information to the file.
🔹 In Kernel House
In Linux kernel, there’s a course of desk to keep up the information for the processes. Every course of has an entry within the desk. Every course of maintains a file descriptor desk, with file descriptors as its indices. Discover that file descriptors 0,1 and a couple of are reserved in every file descriptor desk to symbolize stdin, stdout, and stderr.
The file pointer factors to an entry within the open file desk, which has details about open recordsdata throughout all processes. A number of file descriptors can level to the identical file desk entry. For instance, file descriptor 0, 1 and a couple of factors to the identical open file desk entry.
Since completely different open file desk entries can symbolize the identical file, it’s a waste of assets to retailer the file static data so many instances. We’d like one other abstraction layer referred to as ‘vnode desk’ to retailer the static information.
In every file desk entry, there’s a vnode pointer, which factors to an entry in vnode desk. The static data consists of file sort, operate pointers, reference counts, inode and so on. inode describes a bodily object within the filesystem.
🔹 In Filesystem
The inode array ingredient shops the precise file data, together with permission mode, house owners, timestamps, and so on. inode additionally factors to the information blocks saved within the filesystem.
Over to you: Once we shut a file in a program, have you learnt which entries are deleted in these information constructions?
Are you aware the way you receives a commission at work? Within the US, tech firms often run payrolls by way of Computerized Clearing Home (ACH).
ACH handles retail transactions and is a part of American retail fee methods. It processes transactions in batches, not in real-time. The diagram beneath reveals how ACH direct deposit works with payrolls.
🔹Step 0: Earlier than we will use ACH community, the originator who begins the transactions must open an account at a industrial financial institution as a result of solely banks are allowed to provoke ACH transactions straight. The financial institution is known as ODFI (Originating Depository Monetary Establishment). Then the transaction receiver must authorize the originator for sure sorts of transactions.
🔹Step 1: The originator firm originates wage fee transactions. The transactions are despatched to a Third-party processor like Gusto. The third-party processor helps with ACH-related providers like producing ACH recordsdata, and so on.
🔹Step 2: The third-party processor generates ACH recordsdata on behalf of the originator. The recordsdata are uploaded to an SFTP established by the ODFI. This needs to be achieved by the 7 PM cut-off time, as specified by the ODFI financial institution.
🔹Step 3: After regular enterprise hours within the night, the ODFI financial institution forwards the ACH recordsdata to the ACH operator for clearing and settlement. There are two ACH operators, one is the Federal Reserve (FedACH), and the opposite is EPN (Digital Cost Community – which is operated by a non-public firm).
🔹Step 4: The ACH recordsdata are processed round midnight and made out there to the receiving financial institution RDFI (Receiving Depository Monetary Establishment.)
🔹Step 5: The RDFI operates on the receiver’s financial institution accounts based mostly on the directions within the ACH recordsdata. In our case, the receiver receives $100 from the originator. That is achieved when the RDFI opens for enterprise at 6 AM the subsequent day.
ACH is a next-day settlement system. It means transactions despatched out by 7 PM on in the future will arrive the next morning.
Since 2018, it’s potential to decide on Identical Day ACH so funds could be transferred on the identical enterprise day.
Over to you: ACH is a US monetary community. If you happen to dwell outdoors the US, have you learnt what fee methodology your employer makes use of to ship fee? What’s the distinction between ACH and wire switch?
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