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Hard drives have read/write heads which fly above the spinning disks when the drive is powered. When power is removed, the heads no longer fly... For a long time now, the arms which hold the heads have been designed to “auto-park” the heads away from the disks’ surface, or over a safe “landing zone”, when they lose power¹, but early (up to the mid 80s) hard ...
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Some "informed speculation" based on my "day job" which involves worrying about containment of rotating objects if they break (specifically, rotating parts inside jet engines)
The rotating parts of early disk drives were substantial objects. For example the IBM 350 had 24 inch diameter platters rotating at 1500 RPM, with a rotating mass of about 10 pounds. ...
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For the simple reason that until relatively recently, it was very difficult to make a rewritable optical medium, but it was easy to make a rewritable magnetic medium. Magnetic tape as a recording medium has been a practical technology since the late 1930s, predating the digital computer. For comparison, CD-RW was introduced only in 1997, more than a decade ...
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Floppy disks are harder to get right than hard disks. Early hard disks were enormous; the IBM 350 used fifty 24-inch platters. They were also rather fragile and cumbersome (heavy and power-hungry). To go from a hard disk of this sort to floppy disks required a number of developments: in particular the ability to remove the platters (which came in 1962 with ...
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As noted in some initial comments (but I feel fine answering, as I had the exact same ideas when I read the question), this is a general progression of technology but there are two very specific factors for RAM:
Core Memory -> Integrated Circuits
While many different, very expensive, systems were used in the first computers, including mercury delay lines, ...
answered Jan 9 at 20:19
manassehkatz-Moving 2 Codidact
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My question is if you can fit X number of tracks on a 3.5" platter, why not use the same density on a 5 1/4 platter and have even more tracks? I know there are tradeoffs like latency due to head-travel or cost / complexity if you tried to put multiple heads on the same platter-side but in any case you end up with a capacity that is unobtainable with the ...
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While Stephen Kitt's answer already hits the core, I believe it needs a bit more history, as direct access magnetic storage did start quite a while before the IBM 350.
Drums and Disks
First there were drums. Drums were huge cylinders with a magnetic surface, and a separate head for each track - something that would have been rather impossible with a disk. ...
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I looked at trade periodicals from the time in question, because the intended customer for a hard drive in the early 1980's was almost certainly a business or school (look at the prices, particularly after they are adjusted for inflation!)
PC Magazine only started operations in February of 1982, but there were already several hard drives announced or ...
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Since the price seems to be an issue, I'll suggest a cheap alternative to hard drives.
A IDE Compact Flash card reader with a 4GB or 8GB compact flash card is a cheap combo, still sold (less than 10 euros for the reader on Amazon), consumes not much power (which could be an issue with a hard drive)
The capacity shouldn't be an issue either. For less that 50 ...
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Write speed and endurance.
Optical drive technology has been much slower to write to than magnetic Hard Disk Drives (HDDs).
The erasable optical technologies that made it to mass market were much slower in write time than HDDs and in erase time. Their life before failure was in the 100's of erases.
Optical drive use declined with the advent of USB flash ...
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I'm mostly concerned about RAM.
Why was it so expensive?
It wasn't - at least not once integrated circuit RAM became available in the 1970s. Compared to other chips, RAM was cheaper both per transistor and per package.
Some example prices:-
From an advert in Byte magazine issue #1 (Sept 1975)
8080 CPU: (4,500 transistors) $149.95 = $33 per thousand ...
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By their contents.
When Windows boots, the I/O Supervisor VxD (IOS) uses BIOS interrupt 0x13 services to read sector 0 (the Master Boot Record) of each drive. It then looks at two bytes at offset 0x0DA. If they are zeroes, IOS checks the following four bytes: if they are also zeroes (like in the standard MBR code written by Microsoft’s FDISK), IOS overwrites ...
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There is also this tale that I read recounted in Philip and Alex's Guide to Web Publishing, although the disk pack was intentionally hurled through the wall in a fit of temper:
That night, the Foonly crashed. A Foonly was a clone of the PDP-10, a mainframe computer designed by Digital in the 1960s. MIT and Stanford people loved the PDP-10 but couldn't ...
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I cannot state for certain that it required a hard disk, but using AutoCAD (v1 released Dec.82) without one would have been awkward to well-nigh unbearable. The program itself was huge for the time and used countless data files. I can't imagine running it from floppy.
Even if v1.0 could do so, by the time v2 or v3 was released HD had to be required. It ...
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The physical geometry how many heads the drive actually has is not the same as the logical geometry of how many heads is presented to the PC by the drive.
By translating the geometry, the drive can be fully addressable to up to the maximum of approximately 8 gigabytes in CHS mode, as the IDE interface is limited in CHS mode to 16 heads, 63 sectors and 16383 ...
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TL;DR:
How much did the first hard drives for the IBM PC or Apple || cost, and how big were they?
Ready to use setups started around 3,000+ USD for 5 MiB in 1981
Long (Hi-)Story
As usual defining 'first' is hard, as of course some people always attached drives to their micros way before there wer standard offering - our own Bruce Abbott gives a great ...
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If "a more modern machine" includes systems with ISA, PCI or PCI Express slots, it should be easy enough to retrieve the data from the drives. You'll need a SCSI adapter (known as a host bus adapter, HBA); you can find loads on auction sites, or SCSI4ME and other places (depending on which country you live in). Adaptec cards are very good and well-supported ...
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The ST-238R shown in the image is an RLL (Run Length Limited) drive and will not work correctly with a standard MFM controller, although it has the same ST506 electrical interface and cabling. To read back your data, you will need an RLL controller, which unfortunately are less common than MFM controllers and might not be easy to find.
RLL is an encoding ...
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I have not tried it, but according to the Wikipedia page on the Host Protected Area, one use case was to use large disks on systems whose BIOS could not cope with them. It would therefore seem to be a case of picking a likely-looking modern disk and doing a suitable hdparm -Np command on it from Linux to set a permanent HPA limit. For example, if you wanted ...
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I started working for a newly-certified IBM PC dealer in the UK at the end of 1984. IBM thought we would be selling about 50% twin-floppy PC (PCG) and 50% XT with 10MB hard drive.
In fact, I'm not sure we ever sold a PCG. Perhaps it's because we were focused on accounting and payroll applications for small businesses - not something you would consider with ...
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The tables were built using the parameters for various real hard drives. For example, type 1 is used for the original Shugart drives used in the PC XT (ST506). So the intention was for the drive types to be useful, and at least some of them were; in the linked page, scroll down to the list of Award-486 drive types to see more examples.
Each BIOS ...
15
I've heard of disk heads being propelled at great velocity, though that may be just a scary story told to young people, too.
This is the disc store from a 1965 KDF9:
If a read/write head contacts the spinning disk, it could (I suppose) get ripped off the actuator arm, and thus be accelerated to the extent that it penetrates the glass on the door and causes ...
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To my knowledge, no such driver has ever been written.
Since the very earliest versions, Linux has been a pure 32-bit protected-mode kernel that drove most devices (including disk controllers) directly, without going through the BIOS. The kernel has never had any facility to invoke 16-bit code from kernel mode during normal operation (after early boot); even ...
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That Conner CP-343 drive appears to be a special snowflake, but it's not. It's actually a standard IDE drive, with one exception. That 20-pin interface you're looking at isn't the IDE connector; it's the connector between the drive mechanicals and the controller board that would normally be mounted to the bottom of the drive. Why it's not affixed to the ...
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In order to autoboot any Amiga hard disk, 3 things are needed.
A version of Kickstart that supports boot from HD. This means >= Kickstart 1.3.
A device driver that knows how to speak to the HD controller, such as scsi.device.
A filesystem handler that understands the format of the HD.
I think #1 is simple to understand. This is a function of the Strap (as ...
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Yes, this is possible.
The file utility can recognise many disk partition layouts and file systems. If you connect your drives to your Pentium III system, running a version of Linux, they should appear as /dev/sd? devices. To simplify further analysis, you should copy their contents to a file:
sudo ddrescue /dev/sdX backup.img backup.map
(replacing X as ...
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Didn't people living at that time feel sudden reductions in size/availability as technologies evolved? And if they didn't, why wasn't there a "jump" in memory availability when technology reached a certain state?
Yes - except that since it happened on an annual basis, we got used to having jump after jump after jump in technological capability. It ...
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This is a SCSI device, so it shouldn’t be too hard to get the data off the device. You need the following pieces of equipment:
a SCSI controller, known as a host bus adapter (HBA); these are available for most buses, including USB (getting rare though), PCI and PCI Express (the last two are still easy enough to find, especially second-hand; expect to pay a ...
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